THE  TEXTILE  FIBRES. 

THEIR  PHYSICAL,  MICROSCOPICAL, 

AND 

CHEMICAL    PROPERTIES. 


BY 


J.     MERRITT    MATTHEWS,     PH.D., 

Head  of  Chemical  and  Dyeing   Department^ 
Philadelphia   Textile  School. 


FIRST    EDITION1. 
FIRST     THOUSAND. 


' 
NEW  YORK: 

JOHN  WILEY  &  SONS. 

LONDON  :  CHAPMAN  &  HALL,  LIMITED. 

1904. 


• 


Copyright,   1904, 


J.  MERRITT   MATTHEWS. 


UOBRRT  DHUMMOND,   PK1NTKR,  NEW  YORK 


PREFACE. 


THE  present  book,  it  is  hoped,  will  be  of  assistance  to  both 
the  practical  operator  in  textiles  and  the  student  on  textile 
subjects.  It  has  been  the  outgrowth  of  a  number  of  years  of 
experience  in  the  teaching  of  textile  chemistry,  as  well  as  prac- 
tical observation  in  the  many  mill  problems  which  have  come 
under  the  notice  of  the  author. 

The  textile  fibres  form  the  raw  materials  for  many  of  our 
greatest  industries,  and  hence  it  is  of  importance  that  the  facts 
concerning  them  should  be  systematized  into  some  form  of 
scientific  knowledge.  The  author  has  attempted,  however,  not 
to  allow  the  purely  scientific  phase  of  the  subject  to  overbalance 
the  practical  bearing  of  such  knowledge  on  the  every-day  problems 
of  industry. 

Heretofore,  the  literature  on  the  textile  fibres  has  been  chiefly 
confined  to  a  chapter  or  two  in  general  treatises  on  dyeing  or 
other  textile  subjects,  or  to  specialized  books  such  as  HohnePs 
work  on  the  microscopy  of  the  fibres.  It  has  been  the  author's 
endeavor,  in  the  present  volume,  to  bring  together,  as  far  as 
possible,  all  of  the  material  available  for  the  study  of  the  textile 
fibres.  Such  material  is  as  yet  incomplete,  and  rather  poorly 
organized  at  its  best;  but  it  is  hoped  that  this  volume  may  prove 
a  stimulus  along  the  several  lines  of  research  which  are  available 
in  this  field.  Unfortunately,  the  subject  of  the  textile  fibres 
has  been  lamentably  neglected  by  chemists,  although  there  is 
abundant  indication  that  a  fertile  field  of  research  is  open  to 
chemists  in  this  direction,  and  such  work  would  have  not  only 
a  scientific  value,  but  might  also  lead  to  great  industrial  worth. 
There  is,  as  yet,  relatively  little  known  concerning  the  chemical 


iv  PREFACE. 

constituents  of  the  fibres,  and  the  manner  in  which  varying 
chemical  conditions  affect  the  composition  and  properties  of 
these  constituents.  The  action  of  various  chemical  agents  on 
the  fibre  as  an  individual  has  been  but  very  imperfectly  studied. 
More  work  has  been  done  in  the  microscopical  field  concerning 
the  properties  of  the  fibres;  but  even  here,  the  knowledge  is 
very  incomplete  and  disjointed,  and  especial  attention  is  drawn 
to  the  fact  there  is  yet  a  large  amount  of  work  to  be  done  in  the 
microchemistry  of  the  subject. 

The  author  has  endeavored  to  emphasize  throughout  this 
volume  the  importance  of  the  study  of  the  fibre  as  an  individual, 
for  in  many  cases  it  is  misleading  to  assume  that  the  behavior 
of  the  individual  fibre  is  identical  with  that  of  a  large  mass  of 
fibres  in  the  form  of  yarn  or  cloth.  In  the  latter  case,  the  dif- 
ference in  physical  condition  and  the  action  of  mechanical  forces 
has  an  important  influence.  By  going  back  to  the  study  of  the 
individual  fibre  as  a  basis,  many  explanations  can  be  given  which 
could  not  be  discovered  otherwise. 

It  is  hoped  that  this  book  may  afford  instruction  both  to 
the  manufacturer  and  to  the  student;  assisting  the  former  in 
solving  some  of  the  many  practical  problems  constantly  occurring 
in  the  manufacture  of  textiles,  and  urging  the  latter  on  to  an 
increased  effort  in  the  scientific  development  of  the  subject. 

J.  MERRITT  MATTHEWS. 

PHILADELPHIA  TEXTILE  SCHOOL, 
August,  1904. 


CONTENTS. 


CHAPTER  I. 

PAGB 

CLASSIFICATION  OF  THE  TEXTILE  FIBRES i 

i.  Fibres  Chiefly  Used  for  Textiles.     2.  Animal  and  Vegetable  Fibres. 
3.  Mineral  and  Artificial  Fibres. 


<£> 


CHAPTE 

HAIR  FIBRES 5 

'i.  Wool  and  Hair.     2.  Physiology  and  Structure  of  Wool. 

CHAPTER  III 

THE  CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL  AND  HAIR  FIBRES  . .     28 

i.  Chemical  Constitution.  2.  Chemical  Reactions.  3.  Condition- 
ing of  Wool. 

CHAPTER  IV. 
SHODDY  AND  WOOL  SUBSTITUTES 50 

CHAPTER  V. 

OTHER  HAIR  FIBRES 55 

i.  Fibres  Related  to  Wool.  2.  Mohair.  3.  Cashmere.  4.  Alpaca. 
5.  Vicufta  Wool.  6.  Llama.  7.  Camel's  Hair.  8.  Cow-hair.  9.  Minor 
Hair  Fibres;  Horse-hair;  Cat-hair,  Rabbit-hair. 

CHAPTER  VI. 

SELK;  ITS  ORIGIN  AND  CULTIVATION 68 

i.  Mulberry  Silk.  2.  Wild  Silks.  3.  The  Microscopical  and  Physi- 
cal Properties  of  Silk.  4.  Silk-reeling. 

CHAPTER  VII. 

CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK.  . . 85 

i.  Chemical  Constitution.     2.  Chemical  Reactions.     3    Tussah  Silk. 


vi  CONTENTS. 

CHAPTER  VIII 

PAGE 

THE  VEGETABLE  FIBRES 97 

i.  Basis  of  Vegetable  Fibres.     2.  Classification.     3.  Physical  Struc- 
ture and  Properties. 

CHAPTER  IX. 

COTTON m no 

i.  Origin  and  Growth.     2.  Varieties  of  Cotton.     3.  Vegetable  Silks. 


CHAPTER  X. 

THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 124 

i.  Physical    Structure.       2.  Microscopical     Properties.       3.  Physical 
Properties. 


CHAPTER  XI. 

CHEMICAL  PROPERTIES  OF  COTTON;   CELLULOSE 139 

i.  Chemical   Constitution.     2.  Cellulose.     3.  Chemical   Reactions   of 
Cotton. 


CHAPTER  XII. 

MERCERIZED  COTTON 156 

i.  Mercerizing.     2.  Conditions     of     Mercerizing.     3.  Properties     of 
Mercerized  Cotton. 


CHAPTER  XIII. 
ARTIFICIAL  SILKS;   LUSTRA-CELLULOSE 170 

CHAPTER  XIV. 


\ 177 


i.  Preparation.     2.  Chemical  and  Physical  Properties. 


CHAPTER  XV. 

JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES 184 

i.  Jute.  2.  Ramie  or  China-grass.  3.  Hemp.  4.  Sunn  Hemp. 
5.  Ambari  or  Gambo  Hemp.  6.  New  Zealand  Flax.  7.  Manila  Hemp. 
8.  Sisal  Hemp.  9.  Aloe  Fibre  or  Mauritius  Hrmp.  10.  Pitu  Fibre, 
ii.  Pineapple  Fibre  or  Silk-grass.  12.  Coir  Fibre. 


CONTENTS.  vii 

CHAPTER  XVI. 

PAGE 

QUALITATIVE  ANALYSIS  OF  THE  TEXTILE  FIBRES aefr    2. 

i.  Introductory.  2.  Qualitative  Tests.  3.  Distinction  between  Cot- 
ton and  Linen.  4.  Distinction  between  New  Zealand  Flax,  Jute,  Hemp, 
and  Linen.  5.  Ligneous  Matter.  6.  Goodale's  Table.  7.  Systematic 
Analysis  of  Mixed  Fibres.  8.  Identification  of  Artificial  Silks.  9.  Dis- 
tinction between  True  Silk  and  Different  Varieties  of  Wild  Silk.  10.  Mi- 
cro-analytical Tables. 

CHAPTER  XVII. 

QUANTITATIVE  ANALYSIS  OF  THE  TEXTILE  FIBRES 247 

i.  Wool  and  Cotton  Fabrics.  2.  Wool  and  Silk.  3.  Silk  and  Cotton. 
4.  Wool,  Cotton,  and  Silk.  5.  Analysis  of  Weighting  in  Silk  Fabrics. 

APPENDIX  I. 
MICROSCOPIC  ANALYSIS  OF  FABRICS 269 

APPENDIX  II. 
MACHINE  FOR  DETERMINING  STRENGTH  OF  FIBRES 272 

APPENDIX  III. 

BIBLIOGRAPHY  OF  THE  TEXTILE  FIBRES 275 

INDEX 279 


THE  TEXTILE  FIBRES. 


CHAPTER  I. 
CLASSIFICATION  OF  THE  TEXTILE  FIBRES. 

1.  Fibres  Chiefly  Used  for  Textiles. — In  order  to  be  service- 
able in  a  textile  fabric,  a  fibre  must  possess  sufficient  length  to 
be  woven  and  a  physical  structure  which  will  permit  of  several 
fibres  being  spun  together,  thereby  yielding  a  continuous  thread 
of  considerable  tensile  strength  and  pliability.     Although  there 
are  several  fibres,  such  as  spun  glass,  asbestos,  various  grasses, 
etc.,  which  are  used  for  the  manufacture  of  textiles  in  peculiar 
and  rare  instances,   yet  the  fibres  which  are  employed  to  the 
greatest  extent  and  which  exhibit  the  most  satisfactory  qualities 
are  wool,  silk,  cotton,  and  linen.     All  of  these  possess  an  organ- 
ized structure,  and  are  the  products  of  a  natural  growth  in  life 
processes. 

According  to  Georgevics,  all  textile  fibres  may  be  divided 
into  four  distinct  classes;  and  though  the  same  general  arrange- 
ment is  here  preserved,  the  order  has  been  somewhat  changed 
so  as  to  bring  the  most  prominent  ones  first:  (i)  Animal  fibres; 
(2)  Vegetable  fibres;  (3)  Mineral  fibres;  (4)  Artificial  fibres. 

2.  Animal  and  Vegetable  Fibres. — According  to  their  origin, 
we  may  divide  the  principal  fibres  into  two  general  classes,  those 
derived  from  animal  and  those  derived  from  vegetable  life.     The 
former  includes  wool  and  silk,  and  the  latter  cotton  and  linen. 
Animal   fibres    are    essentially    nitrogenous    substances    (protein 


2  THE   TEXTILE  FIBRES. 

matter),  and  in  some  cases  contain  sulphur.  They  may  be  solid 
filaments  formed  from  a  liquid  secretion  of  certain  caterpillars, 
spiders,  or  molluscs.  Alkalies  readily  attack  the  animal  fibres, 
causing  them  to  be  dissolved,  but  they  withstand  the  action  of 
mineral  acids  to  a  considerable  degree.  Contrary  to  the  vege- 
table fibres,  they  are  readily  injured  if  exposed  to  elevated  tem- 
peratures. Vegetable  fibres  consist  of  plant-cells,  usually  rather 
simple  in  structure  and  forming  an  integral  part  of  the  plant 
itself.  They  are  capable  of  withstanding  rather  high  tempera- 
tures, and  are  not  weakened  or  disintegrated  by  the  action  of 
dilute  alkalies.  They  consist  essentially  of  cellulose,  which  may 
be  in  a  very  pure  form,  or  be  mixed  with  its  various  alteration 
products.  In  some  cases  the  fibre  consists  of  some  cellulose 
derivative  obtained  by  chemical  means,  such,  for  instance,  as 
mercerized  cotton.  Concentrated  alkalies  produce  alteration  prod- 
ucts with  the  vegetable  fibres.  Free  sulphuric  or  hydrochloric 
acid,  even  if  only  moderately  strong,  will  quickly  attack  the 
fibre,  disintegrating  its  organic  structure  and  forming  hydrolyzed 
products.  Nitric  acid,  on  the  other  hand,  forms  nitrocelluloses 
and  various  oxidation  derivatives. 

3.  Mineral  and  Artificial  Fibres. — These  two  classes  of  fibres 
are  of  rare  occurrence  in  the  textile  industry  when  compared 
with  the  extensive  use  of  the  preceding  fibres.  They  find  a  lim- 
ited use,  however,  for  certain  purposes,  and  deserve  to  be  con- 
sidered in  a  systematic  study  of  the  subject.  The  principal, 
and  strictly  speaking  the  only,  mineral  fibre  is  asbestos,  which 
occurs  in  nature  as  the  mineral  of  that  name.  It  is  a  fibrous 
silicate  of  magnesium  and  calcium,  though  often  containing  iron 
and  aluminium  in  its  composition,  especially  in  the  dark-colored 
varieties.  This  mineral,  though  in  the  form  of  a  hard  rock,  can 
be  easily  separated  into  slender  white  fibres,  sometimes  inclining 
towards  a  greenish  color.  The  fibres  of  some  varieties  (Canadian) 
are  curly,  and  afford  the  best  material  for  spinning.  In  general, 
however,  the  fibres  of  asbestos  are  straight  and  glassy  in  structure, 
and  are  difficult  to  spin  into  a  coherent  thread.  In  order  to 
enhance  its  spinning  qualities  it  is  mixed  with  a  little  cotton,  the 
latter  fibre  being  subsequently  destroyed  by  heating  the  woven 


CLASSIFICATION  OF  THE   TEXTILE   FIBRES.  3 

fabric  to  incandescence.  At  the  present  time  quite  a  variety  of 
fabrics  are  manufactured  from  asbestos  fibre,  and  the  high  quality 
of  many  articles  appearing  on  the  market  shows  that  the  art  of 
manipulating  this  substance  has  reached  a  high  degree  of  perfec- 
tion. On  account  of  its  incombustible  nature,  and  as  it  is  a 
very  poor  conductor  of  heat,  it  is  made  into  fabrics  where  these 
qualities  are  especially  desired.  Thus  it  is  frequently  manufac- 
tured into  gloves  and  aprons,  packing  for  steam- cylinders,  the- 
atrical curtains  and  scenery,  lamp-wicks,  etc.  The  latter  use 
of  asbestos  was  known  to  the  ancients,  who  employed  it  for  the 
wicks  of  the  perpetual  lamps  in  their  temples.  It  is  from  this 
fact,  indeed,'that  it  received  its  name,  the  word  " asbestos"  mean- 
ing "unconsumed."  It  was  also  employed  for  napkins  on 
account  of  its  being  readily  cleansed,  it  only  being  necessary  to 
heat  the  fabric  in  a  flame  to  make  it  clean  again.  Asbestos,  in 
general,  is  not  dyed,  and  does  not  undergo  any  chemical  proc- 
esses or  modes  of  treatment.  When  it  is  desirable  to  dye  it  the 
various  substantive  dyes  may  be  used  with  good  effect,  or  the 
color  may  be  applied  by  mordanting  with  albumen. 

The  artificial  fibres  may  be  divided  into  two  groups:  (a) 
those  of  mineral  origin  and  (b)  those  of  animal  or  vegetable 
origin.  In  the  first  division  may  be  classed  such  fibres  as  spun 
glass,  metallic  threads,  and  slag  wool;  in  the  second  division 
may  be  put  the  various  artificial  silks,  such  as  lustra- cellulose 
and  gelatin  silk. 

Fibres  of  spun  glass  are  prepared  by  drawing  out  molten 
glass  in  the  form  of  very  fine  threads ;  colored  glasses  may  be  used 
to  give  rise  to  variously  colored  threads.  Owing  to  its  brittle 
nature  and  lack  of  elasticity,  spun  glass  receives  a  very  limited 
application,  it  being  made  into  various  ornamental  objects,  and 
sometimes  into  cravats.  A  variety  of  spun  glass  known  as  glass 
wool  is  used  to  some  extent  in  the  chemical  laboratory  as  a  filter- 
ing medium  for  liquids  which  would  destroy  ordinary  filter-paper. 
Glass  wool  is  curly,  this  property  being  given  to  it  by  drawing 
out  the  glass  thread  from  two  pieces  of  glass  of  different  degrees 
of  hardness ;  and  by  unequal  contraction  on  cooling,  this  double 
thread  curls  up. 


4  THE   TEXTILE  FIBRES. 

Various  metals  are  at  times  drawn  out  into  threads  for  use  in 
decorative  fabrics.  Gold,  silver,  copper,  and  various  alloys  are 
used  for  this  purpose.  At  the  present  time  metallic  threads  are 
largely  imitated  by  coating  linen  yarns  with  a  thin  film  of  gold  or 
silver. 

Slag  wool  is  prepared  by  blowing  steam  through  molten  slag; 
it  can  scarcely  be  called  a  textile  fibre,  but  it  is  used  in  some 
degree  as  a  packing  material. 

Artificial  silks  are  made  either  from  cellulose  derivatives  or 
gelatin  by  forcing  solutions  of  these  through  fine  capillary  tubes 
and  coagulating  the  resulting  threads  and  subsequently  sub- 
jecting them  to  various  processes  of  chemical  treatment.  As 
these  belong  more  strictly  to  the  class  of  true  textile  fibres,  they 
will  be  given  a  more  extensive  consideration,  in  a  further  section, 
as  being  derivatives  of  cellulose. 


CHAPTER  II. 

WOOL  AND  HAIR  FIBRES. 

i.  THE  woolly,  hair-like  covering  of  the  sheep  forms  the  most 
important  and  the  most  typical  of  the  textile  fibres  which  are 
obtained  from  the  skin  tissues  of  different  beasts.  The  hairy 
coverings  of  a  large  number  of  animals  are  employed  to  a  greater 
or  lesser  extent  as  raw  materials  for  the  manufacture  of  different 
textile  products,  but  those  of  the  various  species  of  sheep  make 
up  "the  great  bulk  of  the  fibres  which  possess  any  considerable 
technical  importance.  Hairs,  derived  from  whatever  species  of 
animals,  have  very  much  in  common  as  to  their  general  physical 
and  chemical  properties;  they  are  also  similar  with  respect  to 
their  physiological  origin  and  growth.  The  hairs,  however,  of 
different  animals,  vary  much  in  the  detail  of  their  special  char- 
acteristics, and  also  with  regard  to  their  adaptability  for  use  in 
the  textile  industry ;  and  the  wool  of  the  sheep  appears  to  exhibit 
in  the  highest  degree  those  specific  properties  which  make  the 
most  suitable  textile  fibre.  These  properties  may  be  enumer- 
ated as  being:  (a)  Sufficient  length,  strength,  and  elasticity, 
together  with  certain  surface  cohesion,  to  enable  several  fibres  to 
be  twisted  or  spun  together  so  as  to  form  a  coherent  and  continu- 
ous thread  or  yarn;  (b)  the  power  of  absorbing  coloring- matters 
from  solution  and  becoming  dyed  thereby,  and  also  the  property 
of  becoming  decolorized  or  bleached  when  treated  with  suitable 
chemical  agents;  (c)  in  addition  to  these  qualities,  which  they 
have  in  common  with  almost  any  textile  fibre,  wool  fibres  also 
possess  the  quality  of  becoming  felted  or  matted  together,  due 
to  the  peculiar  physical  character  of  their  surfaces.  This  property 

5 


6  THE    TEXTILE  FIBRES. 

is  a  most  valuable  one,  as  it  adapts  wool  to  a  large  number  of 
uses  to  which  other  fibres  are  unsuitable. 

Silk  is  also  a  member  of  the  general  group  of  animal  fibres, 
and  though  it  possesses  certain  general  chemical  characteristics 
in  common  with  wool  and  hair,  yet  it  has  an  entirely  different 
physiological  origin,  being  a  filament  of  animal  tissue  excreted 
by  a  certain  species  of  caterpillar,  and  hence  is  totally  different 
from  wool  in  its  physical  properties.^  Wool  may  be  specifically 
designated  as  a  variety  of  hair  growing  on  certain  species  of  mam- 
malia, such  as  sheep,  goats,  etc.  The  unmodified  term  "  wool  " 
has  special  reference  to  the  product  obtained  from  the  different 
varieties  of  sheep.  Cashmere,  mohair,  and  alpaca  are  the  products 
obtained  from  the  thibet,  angora,  and  llama  goats,  respectively. 
Fur  is  also  a  modified  form  of  hair,  but  differs  from  wool  in  many 
of  its  physical  properties,  and  is  not  adapted  for  use  in  the  manu- 
facture of  spun  textiles.  It  is,  however,  largely  employed  for  the 
making  of  hat  felts. 

The  wool-bearing  animals  all  belong  to  the  order  Ruminan- 
tia,  which  includes  those  animals  that  chew  their  cud  or  rumi- 
nate. The  principal  members  of  this  order  are  sheep,  goats,  and 
camels.  The  sheep  belongs  to  the  class  Ovida,  and  occurs  in  a 
number  of  species  which  vary  considerably  in  form  and  geographi- 
cal distribution,  as  well  as  in  the  character  of  the  wool  it  pro- 
duces. Broadly  considered,  naturalists  divide  the  sheep  into  three 
different  classes: 

(a)  Ovis  aries,  commonly  known  as  the  domestic  sheep,  and 
cultivated  more  or  less  in  every  country  in  the  world. 

(b)  Ovis  musmon,   occurring    native    in   the   European    and 
African  countries  bordering  on  the  Mediterranean  Sea. 

(c)  Ovis  ammon,  which  includes  the  wild  or  mountain  sheep 
(argali)  to  be  found  in  Asia  and  America.     The  big-horn  sheep 
of  the  Rocky  Mountains  belongs  to  this  class.* 

*  A  more  detailed  classification  than  the  above  is  given  by  Archer,  who  divides 
the  sheep  into  thirty-two  varieties: 

1.  Spanish,  or  merino  sheep  (Ovis  hispaniam). 

2.  Common  sheep  (Ovis  rusticus). 

3.  Cretan  sheep  (Ovis  strep  siceros). 


WOOL  AND  HAIR  FIBRES.  7 

The  domestic  sheep  is  the  most  important  of  these  classes. 
It  can  hardly  be  said  to  be  indigenous  to  any  one  country,  for  it 
appears  to  have  been  cultivated  by  the  earliest  peoples  in  history, 
and  it  has  spread  over  the  entire  face  of  the  globe  with  the  gradual 
extension  of  civilization  itself.  Different  conditions  of  climate 
and  soil,  of  pasturage  and  cultivation,  appear  to  exert  a  consider- 
able influence  on  the  variety  of  the  sheep  and  on  the  character  of 
the  wool  it  eventually  produces.  Variations  are  also  produced 

4.  Crimean,  sheep  (Ovis  longicandatus) . 

5.  Hooniah,  or  black-faced  sheep  of  Thibet. 

6.  Cago,  or  tame  sheep  of  Cabul  (Ovis  cagia). 

7.  Nepal  sheep  (Ovis  selingia). 
8    Curumbar,  or  Mysore  sheep. 
9.  Garar,  or  Indian  sheep. 

10.  Dukhun,  or  Deccan  sheep. 

11.  Morvant  de  la  chine,  or  Chinese  sheep. 

12.  Shaymbliar,  or  Mysore  sheep. 

13.  Broad-tailed  sheep  (Ovis  laticandatus). 

14.  Many-horned  sheep  (Ovis  polyceratus). 

15.  Pucha,  or  Hindoostan  dumba  sheep. 

1 6.  Tartary  sheep. 

17.  Javanese  sheep. 

18.  Banvall  sheep  (Ovis  Barnal). 

19.  Short-tailed  sheep  of  northern  Russia. 

20.  Smooth-haired  sheep  (Ovis  Ethiopia). 

21.  African  sheep  (Ovis  Grienensis). 

22.  Guinea  sheep  (Ovis  ammon  Guinensis). 

23.  Zeylan  sheep. 

24.  Fezzan  sheep. 

25.  Congo  sheep  (Ovis  dries  congensis). 

26.  Angola  sheep  (Ovis  aries  angolensis). 

27.  Yenu,  or  goitred  sheep  (Ovis  aries  steatiniora). 

28.  Madagascar  sheep. 

29.  Bearded  sheep  of  west  Africa. 

30.  Morocco  sheep  (Ovis  aries  mun&dce). 

31.  West  Indian  sheep  of  Jamaica. 

32.  Brazilian  sheep. 

These  represent  the  naturally  occurring  classes  of  sheep  in  the  different  coun- 
tries; of  course,  a  large  number  have  been  emigrated  and  domesticated  in  other 
countries  than  those  in  which  they  had  their  origin,  which  has  given  rise  to  several 
sub-varieties.  Then,  too,  new  varieties  have  been  formed  by  cross-breeding 
and  intermixing,  which  has  brought  about  a  considerable  variation  in  the  type. 
The  latter  is  also  influenced  very  largely  by  climatic  conditions,  geographical  en- 
vironment, and  character  of  pasturage. 


8  THE   TEXTILE  FIBRES. 

by  cross-breeding  and  intermixing,  and  the  nature  of  the  fibre  has 
been  much  altered  and  improved  by  careful  selection  in  breeding 
and  genealogical  development. 

Sheep  in  their  natural  condition  produce  two  kinds  of  hair: 
the  one  giving  a  long,  stiff  fibre,  which  we  will  call  "  beard-hair  "; 
and  the  other  a  shorter,  softer,  and  more  curly  fibre,  which  we 
will  designate  as  "  wool-hair,"  or  true  wool.  By  domestication  and 
proper  cultivation  the  sheep  can  be  made  to  produce  the  latter 
kind  of  hair  almost  exclusively,  with  but  little  or  none  of  the  hairy 
fibre.  Herein  the  sheep  differs  essentially  from  the  goat,  as  the 
latter  will  always  produce  both  kinds  of  fibre,  though  the  fineness 
and  quality  of  its  hair  may  be  much  improved  by  proper  cultiva- 
tion. In  addition  to  the  above-mentioned  varieties  of  hair,  most 
sheep  grow  more  or  less  of  short,  stiff  hairs,  or  undergrowth; 
these  have  no  value  as  textile  fibres.  It  must  be  mentioned,  how- 
ever, that  the  exact  character  of  the  wool  on  the  individual  sheep 
varies  considerably  with  its  position  in  the  fleece;  on  the  extrem- 
ities of  the  animal  the  wool  becomes  more  hairy  in  nature,  and 
near  the  feet  the  short  undergrowth  of  stiff  hair  is  alone  to  be 
found.  The  texture,  length,  and  softness  of  the  fibre  also  differ 
considerably  in  different  portions  of  the  fleece*  Hence  it  becomes 
necessary,  in  order  to  obtain  a  homogeneous  mixture  of  fibres 
with  properties  as  constant  as  possible,  to  sort  out  the  fibres  of 
the  fleece  into  different  portions,  which  are  put  together  into 
different  grades  of  wool  stock.  This  operation  is  termed  wool- 
sorting  and  grading,  and  is  an  important  step  in  the  manufacture 
of  wool.  Different  varieties  of  wool  may  require  different  sys- 
tems and  degrees  of  sorting,  but  in  general  the  fleece  is  roughly 
divided  into  nine  sections,  given  as  follows: 

(1)  The  shoulders  and  sides  of  the  fleece  give  the  finest  and 
most  even  staples  of  fibre. 

(2)  The  lower  part  of  the  back  yields  a  fibre  of  fairly  good 
staple. 

(3)  The  loin  and  back  give  a  shorter  staple,  and  the  fibre  is 
not  as  strong. 

(4)  The   upper  part  of  tin-   legs  ^ive  a  staple  of  moderate 
length.     The-  fibre  on  this  part  is  frequently  in  the  form  of  loose, 


WOOL  AND  HAIR  FIBRES.  9 

open  locks  and  acquires  a  large  amount  of  burrs  by  brushing 
against  the  spinose  fruit  of  the  plant;  the  presence  of  these  burrs 
considerably  lessens  the  commercial  value  of  the  wool.  South 
American  wool  is  especially  liable  to  be  heavily  charged  with 
burrs. 

(5)  The  upper  part  of  the  neck  gives  a  rather  irregular  staple 
which  is  also  very  frequently  filled  with  burrs. 

(6)  The  centre  of  the  back  gives  a  fine  delicate  staple  similar 
to  that  from  the  loins. 

(7)  The  belly,  together  with  the  wool  from  the  fore  and  hind 
legs  yields  a  poor  staple  and  a  weak  fibre. 

(8)  The  tail  gives  a  short,   coarse,  and  lustrous  fibre,  fre- 
quently containing  a  considerable,  amount  of  kemps, 

(9)  The  head,  chest,  and  shins  give  a  short,  stiff,  and  straight 
fibre,  opaque  and  dead  white  in  color. 

The  merino  sheep,  which  yields  what  is  considered  to  be  the 
finest  quality^of  wool,  appears  to  have  originated  in  Spain,  and  at 
one  time  was  extensively  cultivated  by  the  Moors.  The  exporta- 
tion of  merino  sheep  from  Spain  was  long  guarded  against  with 
great  care,  no  one  being  allowed  to  take  a  live  merino  sheep  out 
of  the  kingdom  of  Spain  under  penalty  of  death.  Later,  how- 
ever, this  sheep  was  brought  into  various  countries,  being  crossed 
with  the  different  local  breeds  with  very  beneficial  results.  A 
German  derivative  of  the  Spanish  merino  known  as  the  Saxony 
Electoral  merino,  gives  perhaps  the  highest  grade  of  fibre  known 
in  Europe.  Australian  sheep  are  mostly  derived  from  merino 
and  other  high- class  stock  and  yield  a  wool  of  the  very  highest 
quality.  The  merino  has  been  cultivated  and  crossed  with  other 
breeds  throughout  the  various  parts  of  the  United  States,  and  the 
latter  country  is  gradually  becoming  a  large  producer  of  middle 
grade  wool. 

2.  Physiology  and  Structure  of  Wool. — Wool,  in  common  with 
all  kinds  of  hair,  is  a  growth  originating  in  the  skin  or  cuticle  of 
the  vertebrate  animals,  and  is  similar  in  its  origin  and  general 
composition  to  the  various  othfer  skin  tissues  to  be  found  in  ani- 
mals, such  as  horn,  nails,  feathers,  etc.  Wool  is  an  organized 
structure  growing  from  a  root  situated  in  the  dermis  or  middle 


10 


THE   TEXTILE  FIBRES. 


layer  of  the  skin;  its  ultimate  physical  elements  being  several 
series  of  animal  cells  of  different  forms  and  properties.  Herein 
it  differs  essentially  from  silk,  which  is  not  composed  of  cells,  but 
is  a  continuous  and  homogeneous  tissue.  The  root  of  the  wool 
fibre  is  termed  the  hair  follicle  (Fig.  i) ;  it  is  a  gland  which  secretes 


FIG.  i.— Section  of  Hair  Follicle. 

C,  cuticle  of  skin;  R,  reta  mucosum;  PL,  papillary  layer;  S,  sebaceous  glands; 
P,  papilla;  B,  bulb  of  hair;  H,  hair;  F,  fibrous  tissue;  SH,  transparent 
sheath. 

a  lymph-like-  liquid,  from  which  the  hair  is  gradually  developed 
by  the  process  of  growth.  The  hair  follicle  also  secretes  an  oil, 
which  is  supplied  to  the  fibre  during  its  growth,  and  serves  t he- 
purpose  of  lubricating  its  several  parts,  giving  it  pliability  and 
elasticity.  In  conjunction  with  tfte  hair  follicle  there  also  occur 
in  the  skin  numerous  sebaceous  glands  which  secrete  a  fatty  or 
waxy  substance,  commonly  known  as  wool-fat.  This  substance 


WOOL   AND  HAIR   FIBRES.  II 

gradually  exudes  from  the  glands  and  coats  the  surface  of  the 
wool  in  rather  considerable  amount  (Fig.  2).  It  affords  a  pro- 
tective coating  to  the  fibre  which  serves  to  preserve  the  latter  from 
mechanical  injury  during  its  growth,  and  also  prevents  the  sev- 
eral fibres  from  becoming  matted  and  felted  together.  In  the 
preparation  of  wool  for  manufacture,  this  fatty  covering  has  to  be 
removed,  the  operation  constituting  the  ordinary  process  of  wool 
scouring.  The  oil,  on  the  other  hand,  which  is  contained  in  the 
substance  of  the  fibre  itself,  and  is  a  true  constituent  of  its  sub- 


I 


FIG.  2. — Wool  Fibre  in  the  Natural  Grease  (X35o). 

The  markings  of  the  scales  are  scarcely  afl^ent  owing  to  the  interstices  being 
filled  \vith  greasy  matter. 

stance,  should  not  be  removed,  as  its  removal  causes  the  fibre  to 
lose  much  of  its  elasticity  and  resiliency.  This  oil  amounts  to 
about  one  per  cent,  of  the  total  weight  of  the  fibre,  whereas  the 
external  fatty  matter  amounts  on  an  average  to  about  30  per  cent. 
Morphologically  considered,  the  wool  fibre  consists  of  three 
distinct  portions:  (a)  A  cellular  marrow,  or  medulla,  which 
frequently  contains  more  or  less  pigment  matter  to  which  the 
wool  owes  its  color;  (b)  A  layer  of  cellular  fibrous  substance  or 
cortical  tissue  which  gives  the  fibre  its  chief  strength  and  elasticity ; 
(c)  An  outer  layer  or  epidermis  of  horn  tissue,  consisting  of  flat- 
tened cells,  or  scales,  the  ends  of  which  generally  overlap  each 
other,  and  project  outwards,  causing  the  edge  of  the  fibre  to 
present  a  serrated  appearance  (Fig.  3).  This  scaly  covering 


12 


THE   TEXTILE  FIBRES. 


gives  the  fibre  its  quality  of  rigidity  and  resistance  to  crushing 
strain ;  it  also  causes  the  fibres  to  felt  together  on  rubbing  against 
one  another  by  the  interlocking  of  the  projecting  edges  of  the 
scales  (Fig.  4). 

Any  one  of  these  three  physical  constituents  may  at  times  be 
lacking  in  a  fibre.  When  the  epidermal  scales  are  absent,  they 
have  simply  been  rubbed  off  by  friction;  this  condition  is  fre- 


FIG.  3.  FIG.  4. 

FIG.  3. — Sections  of  Wool  or  Hair  Fibre. 

a,  cross-section  of  fibre;    b,  longitudinal  section  of  fibre;    A,  epidermal  layer  of 
scales;   5,  cortical  layer  of  fibrous  cells;   C,  *nedullary  layer  of  round  cells. 
FIG.  4. — Diagram  Showing  Felting  Action  of  Wool. 

quently  to  be  found  at  the  ends  of  long  beard-hairs.  The  cortical 
layer  of  fibrous  tissue  is  frequently  but  slightly  developed,  espe- 
cially in  cases  when  tin-  medulla  is  large:  in  some  instances,  indeed 
(as  in  the  hair  of  the  doe),  the  cortical  layer  appears  to  be  totally 
absent  in  the  broadest  parts  of  the  fibre.  The  medulla  is  very 


WOOL  AND  HAIR  FIBRES.  13 

frequently  absent,  or,  at  least,  shows  no  difference  in  structure 
from  the  cells  of  the  surrounding  cortical  layer;  this  occurs 
more  especially  in  the  wool-hairs,  but  is  also  to  be  found  in  beard- 
hairs.  On  the  other  hand,  the  medulla  is  more  largely  developed 
than  the  cortical  layer,  and  becomes  the  principal  part  of  the 
fibre,  as  in  the  beard- hairs  of  the  doe. 

The  microscopic  appearance  of  wool  is  sufficiently  character- 
istic to  distinguish  it  from  all  other  fibres.  Under  even  moder- 
ately low  power  of  magnification  the  scales  on  the  surface  of 
the  fibre  can  be  readily  discerned,  while  neither  silk  nor  the 
vegetable  fibres  present  this  appearance  (Fig.  5).  The  scales 


FIG.  5. — Various  Fibres.     (Bowman.) 
At  Chinese  wool;  B,  merino  wool;  C,  cotton;  D,  silk;  E,  mohair. 

are  more  or  less  translucent  in  appearance,  and  permit  of  the 
under  cortical  layer  being  seen  through  them.  The  exact  nature 
and  structure  and  arrangement  of  the  scales  differ  considerably 
with  different  varieties  of  wool.  In  fine  merino  wools,  for  in- 
stance, the  individual  scales  are  in  the  form  of  cylindrical  cusps, 
one  somewhat  overlapping  the  other;  that  is  to  say,  a  single 
scale  completely  surrounds  the  entire  fibre  (Fig.  6).  In  some 
varieties  of  wool,  on  the  other  hand,  two  or  more  scales  occur  in 
the  circumference  of  the  fibre.  In  some  cases  the  edges  of  the 
scales  are  smooth  and  straight  (Fig.  7),  and  this  appears  to  be 
especially  characteristic  of  fine  qualities  of  wool;  the  coarser 
species,  on  the  other  hand,  possess  scales  having  serrated  wavy 


THE   TEXTILE  FIBRES. 


edges.     Usually  such  scales  are  much  broader  than  they  are  long 
and  are  very  thin  (Fig.  8).    The  length  of  the  free  or  projecting 


\ 


FIG.  6. — Typical  Wool  I  ihri-s  (X5oo). 

From  a  camera  lucida  micrograph,  showing  the  irregular  surface  scales  and  the 
faint  striations  of  the  underlying  fibrous  layer  of  cortical  tissue;  the  presence 
of  the  medullary  cells  is  also  plainly  visible  in  one  fibre. 


FIG.  7. — Wool  Fibre  (X3>o). 
With  smooth,  straight  scales  of  a  non-felting  type. 

edge  of  the  scale  is  also  a  very  variable  factor;  in  some  wools  the 
scale  is  free  from  the  body  of  the  fibre  for  about  one-third  of  the 


WOOL   AND  HAIR  FIBRES,  15 

length  of  the  former,  and  in  consequence  the  scale  protrudes  to  a 
considerable  extent;  such  wool  would  be  eminently  suitable 
for  the  preparation  of  material  which  requires  to  be  much  felted 
(Fig.  9).  In  other  wools,  the  free  edge  of  the  scale  amounts  to 
almost  nothing,  and  the  separate  members  fit  down  on  one  another 
closely,  and  are  arranged  like  a  series  of  plates.  Wools  of  this 
class  are  more  hair-like  in  texture,  being  stiffer  and  straighter, 


FIG.  8.  FIG.  9- 

FIG.  8. — American  Merino  Wool.     (Bowman.) 
FIG.  9. — Australian  Botany  Wool.     (Bowman.) 

In  fibres  A  and  B  irregularities  in  diameter  may  be  noticed;  but  in  fibres  C  and  D 
the  diameter  is  very  uniform. 

and  not  capable  of  being  readily  felted  (Fig.  10).  The  wool- 
hairs  (the  long,  stiff  fibres  which  have  already  been  mentioned  as 
occurring  to  a  greater  or  lesser  degree  in  nearly  all  wools,  also 
known  as  beard-hairs)  usually  possess  this  structure.  The  felt- 
ing quality  of  wool  is  much  increased  by  treatment  with  acid  or 
alkaline  solutions,  or  even  boiling  water,  the  effect  being  to  open 
up  the  scales  to  a  greater  extent,  so  that  they  present  a  much 
larger  free  margin  and  consequently  interlock  more  readily  and 
firmly.  Woolen  yarns,  and  woven  materials  made  from  such 
yarns,  felt  much  more  easily  than  worsted  yarns,  due  to  the  fact 
that  the  fibres  of  the  former  lie  in  every  direction  and  the  inter- 
locking of  the  scales  takes  place  more  easily. 

In  some  varieties  of  wool  fibre  the  scales  have  no  free  edge  at 
all,  but  the  sides  fit  tightly  together  with  apparently  no  overlap- 


i6 


THE   TEXTILE  FIBRES. 


ping;  in  such  fibres  the  surfaces  of  the  scales  are  also  more  or 
less  concave  (Fig.  n).  This  structure  only  occurs  with  thick, 
coarse  varieties  of  wool.  Frequently  at  the  ends  of  the  wool 
fibre,  where  the  natural  point  is  still  preserved  (as  in  the  case  of 


FIG.  io.— Wool  Fibre  with  Plate-like  Scales.     (Hohnel.) 

A,  portion  of  fibre  with  isolated  medullary  cells  at  «,  and  smooth  scales  e  fitting 
together  like  plates;  B,  portion  of  fibre  showing  medullary  cylinder  at  m. 

lamb's  wool  from  fleeces  which  have  not  been  previously  sheared), 
the  scales  are  more  or  less  rubbed  off  and  the  under  cortical 
layer  becomes  exposed  (Fig.  12);  this  appearance  is  quite  charac- 
teristic of  certain  wools.  In  diseased  fibres  the  epidermal  scales 
may  also  be  lacking  in  places,  causing  such  fibres  to  be  very 
weak  at  these  points  (Fig.  13). 

In  most  varieties  of  wools  the  scales  of  the  epidermis  may  be 
readily  observed  even  under  rather  low  powers  of  magnification, 
while  under  high  powers  the  individual  scales  may  be  seen  over- 
lapping one  another  like  shingles  on  a  roof,  and  showing  pointed, 


WOOL  AND  HAIR  FIBRES. 


II 


••i 


FIG.  ii.  FIG.  12. 

FIG.  ii. — Wool  Fibre  with  Concave  Scales.     (Hohnel.) 

m,  medullary  cylinder  consisting  of  several  rows  of  cells;  e,  concave  scales  arranged 
in  a  plate-like  manner. 

FIG.  12.— Showing  Wool  Fibre  with  Scales  Rubbed  Off.     (Hohnel.) 
e,  residue  of  epidermis;    notice  the  coarse  striations  of  the  cortical  layer  under- 
neath the  epidermis. 


FIG.  13. — Kempy  Wool  Fibres.     (Bowman.) 

A,  fibre  with  incomplete  development  of  scales;    B,  fibre  with  scales  undeveloped 
in  certain  parts  only;  C  and  D,  diseased  fibres. 


1 8  THE   TEXTILE  FIBRES. 

thickened  protuberances  at  the  edges.  When  the  fibre  becomes 
more  hair- like  in  nature,  such  as  mohair,  alpaca,  camel's  hair,  etc., 
it  is  more  difficult  to  observe  the  individual  scales,  as  these  fuse 
together  to  a  greater  or  lesser  degree,  until  the  true  hair  fibre  is 
reached,  which  exhibits  scarcely  any  markings  of  scales  at  all 
under  ordinary  conditions.  By  treatment  with  ammoniacal 
copper  oxide,  however,  the  interscalar  matter  is  dissolved  away, 
and  even  with  true  hair  the  scaly  nature  of  the  surface  may  be 
observed.  Bowman  gives  the  approximate  comparative  number 
of  scales  in  different  varieties  of  wool  as  follows: 

Wool.  Scales,  per  inch.     Diam.  of  Fibre  (ins.). 

East  Indian 1000  o .  00143 

Chinese 1200  0.00133 

Lincoln 1400  o .  00091 

Leicester 1450  0.00077 

Southdown 1500  o .  00080 

Merino 2000  o .  00055 

Saxony 2200  o. 00050 

The  epidermal  lajer  of  scales  imparts  to  the  wool  fibre  its 
characteristic  quality  of  lustre.  Since  the  lustre  of  any  surface 
is  due  to  the  unbroken  reflection  of  light  from  that  surface,  it  may 
be  readily  understood  that  the  smoother  the  surface  of  the  fibre, 
the  more  lustrous  it  will  appear.  When  the  epidermal  scales 
are  irregular  and  uneven,  and  have  projecting  points  and  rough- 
ened edges,  the  surface  of  the  fibre  will  naturally  not  be  very 
smooth  and  uniform,  and  consequently  will  reflect  light  in  only 
a  broken  and  scattered  manner.  Such  fibres  will  not  have  a 
high  degree  of  lustre.  On  the  other  hand,  when  the  scales  are 
regular  and  uniform  in  their  arrangement,  and  their  edges  are 
more  or  less  segmented  together  to  form  a  continuous  surface^ 
the  fibre  will  be  smooth  and  lustrous.  As  a  rule,  the  coarser  and 
straighter  fibres  are  the  more  lustrous,  as  they  approximate 
more  closely  to  the  structure  of  hair,  which  has  a  smooth  surface. 
The  lustre  of  the  fibre  being  dependent  on  the  polished  surface 
of  the  scales  is  influenced  largely  by  any  condition  which  may 
affect  the  latter.  Treatment  with  chemical  agents,  for  instance, 
which  will  corrode  the  horny  tissue  of  the  scales,  will  seriously 
affect  the  lustre,  as  is  evidenced  by  allowing  alkaline  solutions  to 


WOOL   AND  HAIR  FIBRES.  19 

act  on  lustrous  wool  fibres.  High  temperatures  (and  especially 
dry  heat)  corrodes  the  epidermal  scales  and  shrivels  them  up, 
causing  the  fibre  to  lose  its  lustre.  In  the  various  mechanical 
processes  through  which  the  wool  must  pass  in  the  course  of  its 
manufacture,  the  scales  of  the  fibre  suffer  more  or  less  injury, 
being  torn  apart,  roughened,  and  loosened  from  the  surface.  In 
order  to  minimize  the  extent  of  this  injury  the  wool  is  generally 
oiled,  so  that  the  surface  of  the  fibres  may  be  properly  lubricated. 

The  rigidity  and  pliability  of  the  wool  fibre  is  also  largely 
conditioned  by  the  nature  of  its  epidermal  scales.  If  these  fit 
over  one  another  loosely  with  considerable  length  of  free  edge, 
the  fibre  will  be  very  pliable  and  plastic,  soft  and  yielding,  also 
easily  felted.  Whereas,  if  the  scales  fit  closely  against  one  another 
and  have  little  or  no  freedom  of  movement,  the  fibres  will  be  stiff 
and  resistant,  and  not  easily  twisted  together  nor  felted. 

The  ccntigal  layer,  or  true  fibrous  portion  of  the  fibre,  forms 
the  major  constituent  of  wool.  It  consists  principally  of  more  or 
less  elongated  cells,  and  often  presents  a  distinctly  striated  appear- 
ance, the  striations  being  visible  through  the  translucent  layer 
of  scales.  The  individual  cells  measure  from  0.0025  in.  to  0.0014 
in.  in  length,  and  from  0.00066  in.  to  0.00050  in.  in  diameter, 
hence  are  elliptical  in  form.  The  cells  may  be  disintegrated 
from  one  another  by  a  careful  treatment  with  caustic  alkali.  To 
this  cortical^tissue  the  fibre  chiefly  owes  its  tensile  strength  and 
elasticity,  ^when  the  fibre  is  fine  in  staple,  the  cortical  cells 
exhibit  more  or  less  unevenness  in  their  growth  and  arrangement, 
with  the  result  that  the  fibre  is  contracted  on  one  side  or  the 
other,  giving  rise  to  the  wavy  or  curled  appearance  of  such  wools. 
It  is  best,  perhaps,  to  speak  of  the  wool  being  "  wavy  "  rather  than 
"  curled,"  as  the  latter  implies  usually  a  spiral  development  which 
involves  a  twisting  of  the  fibre,  and  in  wool,  as  a  rule,  this  does  not 
occur.  Coarse  wools  seldom  exhibit  this  wavy  structure,  or  only 
to  a  slight  degree,  the  waves  being  long  and  irregular;  some  fine 
stapled  wools,  on  the  other  hand,  possess  short  and  very  regular 
waves.  This  property  of  the  fibre  adds  much  to  its  spinning 
qualities,  and  also  to  the  resiliency  of  the  yarn  or  fabric  into 
which  it  is  manufactured.  Wool- hairs  exhibit  much  less  develop- 


20  THE   TEXTILE  FIBRES. 

ment  of  waves  than  the  true  wool  fibres,  and  the  more  closely  the 
animal  fibres  approximate  to  the  structure  of  ordinary  hair,  the 
less  pronounced  are  the  waves.  Sheep's  wool  is  more  wavy 
than  that  derived  from  allied  species,  such  as  the  various  goats, 
camel,  etc.  Mohair,  for  instance,  exhibits  no  wavy  structure 
at  all.  The  exact  cause  which  determines  the  wavy  quality  of 
wool  is  but  ill-defined;  there  appears,  however,  to  be  some  con- 
nection between  the  degree  of  curl,  the  diameter  of  the  fibre, 
and  the  number  of  scales  per  inch.  The  following  table,  given 
by  Bowman,  shows  the  relation  between  the  number  of  waves  and 
the  diameter  of  the  fibre: 

Wool.  Waves   per  inch.        Diameter  of  Fibre  (ins.). 

English  merino 24-30  0.00064 

Southdown 13-18  0.00078 

"         11-16  o.ooioo 

Irish 7-11  o .  ooi  20 

Lincoln 3~  5  0.00154 

Northumberland 2-4  0.00172 

The  waviness  of  the  wool  fibre  may  be  temporarily  removed  by 
wetting  with  hot  water  and  drying  while  in  the  stretched  condition. 

In  tensile  strength  and  elasticity,  the  wool  fibre  varies  within 
large  limits,  depending  on  the  breed  and  quality  of  the  sheep, 
and  also  the  diameter  of  the  fibre  and  the  part  of  the  fleece  from 
which  it  was  derived.  The  strength  of  wool,  and  of  animal  hairs 
in  general,  is  due  to  the  peculiar  structure  of  the  fibre.  In  the 
first  place,  the  external  sheath  of  horny  tissue  of  flattened  cells 
which  take  the  form  of  scales,  offers  considerable  resistance  to 
crushing  strains,  and  are  also  locked  rather  firmly  together  in 
the  direction  of  the  length  of  the  fibre;  this  has  a  tendency  to 
resist  any  diminution  in  the  diameter  of  the  fibre  which  would  be 
felt  when  the  latter  is  stretched.  Then,  too,  the  internal  cortical 
cells  of  the  fibre  are  so  arranged  as  to  present  a  very  firm  struc- 
ture, being  firmly  interlaced  together,  consequently,  they  offer 
considerable  resistance  to  rupture.  It  has  been  noticed  by  a 
microscopical  examination  of  a  broken  fibre  that  the  cells  them- 
selves are  never  ruptured,  but  only  pulled  apart  from  one  an- 
other; this  is  evidence  that  the  cell- wall  is  of  a  strong  texture. 
The  latter  is  probably  formed  of  a  continuous  tissue  which  is  less 


WOOL  AND  HAIR  FIBRES. 


21 


than  0.0002  inch  in  thickness,  as  under  the  highest  powers  of 
the  microscope  it  exhibits  no  evidence  of  structural  elements. 
Bowman  gives  the  following  table  which  records  the  average 
results  of  a  number  of  experiments  on  the  strength  and  elas- 
ticity of  the  wool  fibre: 


Wool. 

Tensile 
Strength, 
grams. 

Elasticity, 
per  cent. 

Diameter, 
ins. 

Human  hair  

106 

36.6 

o  00332 

Lincoln  Wool  

** 

28.4 

o  .  00181 

Leicester 

•?! 

27    3 

o  00164 

Isorthumberland 

28 

27    O 

O    OOIJ.Q 

Southdown  wool 

5Q 

26  8 

o  ooooo 

Australian  merino.  .  .             

3    2 

•5-7    r 

o  000^2 

Saxonv  merino  

2.  < 

27    ? 

O    OOO34. 

"\Johair 

,8 

2O    O 

Alpaca 

97 

2  t     2 

It  is  interesting  to  compare  these  figures  of  tensile  strength  for 
equal  cross-sections  of  fibre.  As  the  cross-section  varies  with  the 
square  of  the  diameter,  by  taking  the  ratio  of  the  latter  numbers 
and  multiplying  by  the  tensile  strength,  a  figure  is  obtained  which 
represents  the  tensile  strength  for  equal  diameters  of  fibres.  In 
this  manner  the  following  table  has  been  calculated,  taking  human 
hair  as  the  standard  for  comparison,  as  it  has  the  largest  diameter : 

Human  hair 100 

Lincoln  wool 96. 4 

Leicester IJ9-9 

NoBthumberland 130 . 9 

Southdown  wool 62 . 3 

Australian  merino 122 . 8 

Saxony  merino 224 . 6 

Mohair 136 . 2 

Alpaca 358 . 5 

Cotton  (Egyptian) 201 . 8 

It  will  be  noticed  from  this  table  that  Saxony  merino  wool  is 
by  far  the  strongest  of  the  different  grades  of  wool.  It  is  also 
interesting  to  note  that  cotton  is  considerably  stronger  than  the 
majority  of  wools. 

The  medulla,  or  marrow,  of  the  wool  fibre  consists  of  round  or 
slightly  flattened  cells,  usually  somewhat  larger  in  section  than 


22  THE   TEXTILE  FIBRES. 

those  comprising  the  cortical  layer.  The  size  of  the  medulla 
varies  considerably  in  different  varieties  and  grades  of  wool,  and 
even  shows  large  variations  in  fibres  from  the  same  fleece.  At 
times  it  may  occupy  as  much  as  one-quarter  to  one-third  of  the 
entire  diameter  of  the  fibre;  and  again,  it  may  be  reduced  to 
almost  a  line,  or  even  disappear  completely.  Wool-hairs  exhibit 
the  presence  of  a  distinct  medulla  more  frequently  than  the  true 
wool  fibres.  The  latter  mostly  show  scarcely  any  inner  structure 
at  all,  though  at  times  there  may  be  noticed  isolated  medullary 
markings,  but  usually  the  fibre  is  so  transparent  that  it  presents 
no  markings  at  all.  In  camel's  hair,  however,  the  medullary 
portion  shows  up  very  distinctly,  in  some  fibres  appearing  as  a 
continuous  dark  band  occurring  about  three-fourths  of  the  width 
of  the  fibre,  while  in  other  fibres  it  shows  a  well-defined  granular 
structure.  In  hairs  of  some  other  animals  the  medullary  part 
exhibits  a  structure  which  is  distinctly  characteristic  of  the  fibre; 
in  the  hair  of  the  cat,  for  instance,  the  medullary  cells  appear  in 
a  reticulated  form,  and  in  the  hair  of  the  rabbit  they  occur  as  a 
series  of  laminae  very  regularly  superposed  on  each  other.  The 
medullary  cells  frequently  contain  pigment  matter,  either  con- 
tinuously or  in  isolated  cells;  and  this  may  occur  even  in  fibres 
usually  classified  as  white  wool.  Sometimes  the  pigment  per- 
meates not  only  the  medulla,  but  also  the  cells  of  the  cortical 
layer,  in  which  case  the  fibre  as  a  whole  appears  colored.  To 
this  class  belong  the  variously  colored  wools,  ranging  from  a 
light  brown  to  almost  a  black.  The  hair  of  camels,  goats,  and 
other  animals  is  also  more  or  less  colored,  and  to  a  much  more 
general  extent  than  sheep's  wool.  The  medulla  may  consist  of  a 
single  series  of  cells,  or  of  several  series  arranged  side  by  side; 
sometimes  these  cells  occur  in  a  discontinuous  and  rather  irregu- 
lar manner,  the  intervening  spaces  of  the  medulla  being  filled 
with  air.  The  function  of  the  medulla  is  to  provide  the  living 
fibre  with  an  inner  canal  for  the  flow  of  juices  whereby  it  receives 
nourishment  for  its  growth.  It  also  adds  much  to  the  porosity  / 
of  the  fibre,  forming  a  capillary  tube  whereby  the  latter  may  suck 
up  solutions  of  various  kinds,  such  as  dyestuffs,  different  salts, 
etc.,  allowing  these  to  gradually  permeate  through  the  cortical 


WOOL  AND  HAIR  FIBRES.  23 

layer  as  well.  The  epidermal  layer  of  scales  is  rather  impervious 
to  the  transpiration  of  solutions,  and  only  permits  of  their  en- 
trance into  the  fibre  at  the  joints  of  the  scales,  so  it  may  be  seen 
that  the  medulla  of  the  fibre  becomes  an  important  adjunct  in 
1  the  chemical  treatment  of  wool  in  the  processes  of  mordanting, 
dyeing,  and  bleaching.  It  might  also  be  noted,  in  this  connec- 
tion, that  the  epidermal  scales  become  but  slightly,  if  at  all, 
dyed  when  various  coloring-matters  are  applied  to  the  fibre,  but 
remain  clear  and  translucent.  Hence  it  may  be  readily  under-  / 
stood  that  if  two  samples  of  wool  are  dyed  simultaneously,  the 
one  consisting  of  fibres  having  small  and  open  scales,  while  the 
other  has  a  thick  and  highly  resistant  epidermis,  the  resulting 
color  on  the  two  samples  will  have  a  different  quality  or  tone, 
due  to  the  influence  on  the  latter  of  the  uncolored  and  trans- 
lucent scales.  In  wools  where  this  influence  is  very  marked  it  is 
almost  impossible  to  obtain  rich  and  full  shades  of  color,  due  to 
the  transparency  and  lustre  of  the  surface,  which  allows  of  con- 
siderable white  light  being  refracted  through  the  fibre  along 
with  the  reflected  color.  This  also  explains  the  well-known  fact 
that  the  longitudinal  surface  of  the  fibre  in  many  cases  presents 
a  different  tone  of  color  than  the  cut  ^nds,  the  latter  usually  being 
richer  and  deeper  in  tone;  as  may  be" noticed  in  cut-pile  fabrics, 
such  as  occur  in  rugs,  plushes,  etc.  In  some  cases  the  epidermal 
layer,  instead  of  being  highly  translucent,  is  opaque  and  white; 
this  is  true  of  many  varieties  of  coarse  wool-hairs,  and  such  fibres 
as  cow-hair,  etc.  In  such  instances  the  dyed  fibre  will  lack 
liveliness  of  tone  and  appear  rather  dead  and  flat.  The  further 
discussion  of  this  interesting  subject  must  be  dealt  with  in  more 
detail  in  the  study  of  shade  matching.  Attention  ;s  merely  called 
to  it  at  this  point  in  order  to  emphasize  more  clearly  the  funda- 
mental cause  of  these  differences  in  color  phenomena  as  lying 
in  the  structure  of  the  fibre  itself. 

Frequently,  through  disease  or  other  natural  causes,  the 
medulla  of  the  wool  fibre  is  imperfectly  developed,  in  consequence 
of  which  the  wool  will  not  absorb  solutions  readily,  and  hence 
will  not  be  dyed  (or  mordanted)  at  all,  or  only  slightly.  These 
fibres,  which  are  known  as  kemps,  will  occur  through  the  mass 


24  THE   TEXTILE  FIBRES. 

of  the  wool  as  undyed  streaks,  and  will  give  the  yarn  or  fabric  a 
speckled  appearance.  Not  only  may  this  condition,  however, 
be  brought  about  by  natural  causes,  but  it  may  at  times  be  the 
result  of  artificial  manipulation  during  manufacturing  processes. 
There  is  a  certain  class  of  wool,  for  instance,  known  in  trade  as 
pulled  wool;  this  is  obtained  from  the  pelts  of  slaughtered  sheep, 
and  is  usually  removed  from  the  skin  by  the  action  of  lime,  the 
fibres  being  pulled  out  by  the  roots.  In  the  process,  the  medulla 
becomes  stopped  up  with  solid  insoluble  particles  of  lime,  which 
1  is  also  true  of  the  end  pores  of  the  cortical  layer  and  the  joints  of 
the  scales.  As  a  consequence,  the  fibre  is  very  difficult  to  impreg- 
nate with  solutions,  and  will  remain  more  or  less  completely 
undyed.  This  non-porous  character  is  also  enhanced,  perhaps, 
by  the  fact  that  the  fibre  does  not  possess  a  freshly  cut  end,  but 
still  retains  the  root,  which  is  more  or  less  rounded  off  and  closed 
by  the  coagulation  and  hardening  of  the  juices  in  the  hair  follicle. 

The  medulla,  as  a  rule,  is  more  developed  in  beard- hairs  than 
in  wool-hairs,  and  more  in  coarse  grades  of  wool  than  in  the 
finer  qualities.  There  also  appears  to  be  more  or  less  relation 
between  the  breed  of  the  wool  and  the  morphological  charac- 
teristics of  the  medullary  cells,  although  this  is  a  subject  which 
as  yet  has  been  but  little  studied.  At  times  the  medullary  cells 
exhibit  but  little  differentiation  from  those  of  the  cortical  layers, 
and  these  two  portions  of  the  fibre  become  continuous  in  their 
appearance,  that  is  to  say,  no  line  of  demarcation  can  be  drawn 
between  the  medulla  and  the  surrounding  cortical  layer. 

In  length,  the  wool  fibre  varies  between  large  limits,  not  only  in 
different  sheep,  but  also  in  the  same  fleece.  Generally  speaking, 
the  length  may  be  taken  as  being  between  i  and  8  ins.  The 
diameter  of  the  fibre  is  also  very  variable,  even  m  the  same 
4  fleece,  but  may  be  taken  as  averaging  from  0.004  to  0.0018  in.* 
According  to  their  length  of  staple,  wool  fibres  are  graded  into 
two  classes:  lops  and  noils.  The  former  includes  the  longer 
stapled  fibres,  which  are  combed  and  spun  into  worsted  yarns,  to 

*  According  to  Hohnel,  the  diameter  of  sheep's  wool  varies  from  10  to  100  /t 
(the  expression  ji  =  -rifoo  mm.);  and  according  to  Cramer,  the  thickness  of  the 
hairs  from  one  and  the  same  fleece  may  vary  from  12  to  85  /z.  . 


WOOL   AND  HAIR  FIBRES.  25 

be  manufactured  into  trouserings,  dress-goods,  and  such  fabrics 
as  are  not  fulled  to  any  extent  in  the  finishing.  The  latter  class 
consists  of  the  short- stapled  fibres,  which  are  carded  and  spun  into 
woolen  yarns  to  be  used  for  weft  and  all  classes  of  goods  which 
are  fulled  more  or  less  in  the  finishing  operations,  where  a  felting 
together  of  the  fibres  is  desired.  On  comparing  worsted  and 
woolen  yarns,  it  will  be  noticed  that  the  former  are  fairly  even 
in  diameter  and  the  individual  fibres  lie  more  or  less  parallel 
to  each  other;  whereas  in  woolen  yarns  the  diameter  Js  very 
uneven,  and  the  fibres  lie  in  all  manner  of  directions. 

The  quality  of  wool  obtained  from  sheep  depends  very  largely 
on  the  breed,  on  climatic  conditions,  and  nature  of  the  pasturage 
on  which  the  sheep  feed.  Australia  appears  to  possess  the  cli- 
matic conditions  best  adapted  for  wool-growing.*  With  regard 
to  the  nature  of  the  pasturage  it  has  been  found  that  grass  from 
chalky  soils  gives  rise  to  a  coarse  wool,  whereas  that  from  rich, 
loamy  soils  produces  fine  grades  of  wool.f  As  a  rule,  the  sheep 

*  Other  conditions  being  equal,  long  droughty  seasons  in  wool-growing  dis- 
tricts will  cause  the  fibre  to  be  much  shorter  than  otherwise. 

t  Utah  wools,  for  instance,  are  harsh  and  stairy  compared  to  Wyoming  wools. 
This  is  due  to  the  alkali  in  the  soil  in  Utah  and  the  dryness  of  the  climate.  The 
alkali  in  the  soil  and  the  effect  which  it  has  upon  the  water  which  the  sheep  drink 
have  a  tendency  to  take  the  life  out  of  the  wool  and  weaken  the  staple.  The  more 
close  and  uniform  the  fibres  lie,  the  better  will  be  the  combing  qualities  of  the  wool. 
The  Utah  wools  in  this  respect  are  inferior  to  the  Wyomings,  Idahos,  and  Mon- 
ta-as,  especially  the  wools  grown  in  southern  Utah.  In  northern  Utah  the  wools 
are  longer  than  in  southern  Utah,  but  there  are  very  few  Utahs  either  north  or 
south  which  are  fit  for  combing.^T'he  heaviest  shrinkage  wools  generally  come 
from  eastern  Oregon  and  Nevada.  The  degree  of  shrinkage  depends  to  a  con- 
siderable extent  on  the  season  in  which  the  wools  were  grown.  A  wet  season 
and  long-continued  rains  will  wash  much  dirt  and  dust  out  of  the  wools,  thus  leav- 
ing them  lighter.  The  lightest  shrinkage  wools  come  from  Virginia  and  Ken- 
tucky and  the  Blue  Grass  region,  where  medium  wools  are  grown,  where  the  sheep 
are  cleaner,  the  range  better,  and  the  country  hilly,  and  where  comparatively 
little  sand  and  dirt  work  their  way  into  the  fleece.  The  shrinkage  of  washed 
fleeces  ranges  from  55^  to  35°,' .  Unwashed  Indiana  wools  shrink  38%  to  43%. 
Mi— ouris  will  shrink  around  43%  to  45%.  Illinois,  45%  to  47%-  California 
wools  shrink  55^  to  ~2c/(,  depending  on  the  part  from  which  they  come.  The 
heaviest  shrinkage  wools  are  in  southern  California,  because  of  the  presence  of 
more  sand  and  dirt,  and  inferiority  of  the  range.  Texas  spring  wools  shrink 
anywhere  from  64%  to  72%,  and  the  fall  wools  58%  to  64%.  Territory  wools 
.shrink  from  55%  up  to  73^.  Idahos  on  the  medium  order  will  not  shrink  over 


26  THE   TEXTILE  FIBRES. 

which  yield  the  best  qualities  of  wool  give  the  poorest  quality  of 
mutton. 

Unhealthy  conditions  of  the  sheep  almost  always  influence 
the  fibre  during  that  period  of  its  growth.  If  the  sheep,  for 
example,  is  suffering  from  indigestion,  cold,  lack  of  proper  nour- 
ishment, etc.,  the  fleece  during  that  time  will  develop  tender 
fibres;  when  the  sheep  regains  its  normal  condition  of  health,  the 
fibre  becomes  strong  again.  Thus  the  fleece  may  have  tender 
strata  through  it  which  will  considerably  affect  the  fibre  and  its 
uses.  These  tender  spots,  of  course,  render  the  wool  unfit  for 
combing  purposes,  and  it  must  go  into  the  "clothing"  class,  and 
will  consequently  sell  for  less  money,  other  things  being  equal. 
It  is  no  great  injury  to  the  wool,  however,  aside  from  spoiling  it 
for  combing,  as  the  wool,  after  it  has  passed  the  tender  spot,  grows 
fully  as  well  as  before  the  sheep  was  ill.  When  sheep  have  been 
afflicted  with  scab,  the  latter  shows  itself  in  tender  wool  at  the 
bottom  of  the  fibre.  The  scab  leaves  a  pus-like  substance  which 
adheres  to  the  bottom  of  the  fibres  and  dries  there.  Vermin  on 
sheep  have  an  influence  on  the  wool;  these  creatures  leave  dis- 
colorations  on  the  fibre  which  cannot  be  removed  by  scouring. 
The  wool,  being  "off  color,"  does  not  sell  as  well,  and,  moreover, 
the  fibre  is  liable  to  be  tender. 

As  to  the  amount  of  wool  to  be  obtained  from  each  sheep, 
it  may  be  said  that  the  average  yield  is  from  4  to  15  Ibs.,  though 
in  some  South  American  varieties  the  fleece  may  weigh  as  high  as 


55%-  Wyoming  wools  on  the  fine  and  fine  medium  order  shrink  65%  to  72%. 
The  Montanas  shrink  on  the  average  63%  to  69%  for  fine  and  fine  mediums,  and 
57%  t°  60%  f°r  mediums.  The  shrinkage  on  Arizona  wools  will  range  from 
66%  to  73%,  but  they  will  spin  to  finer  counts  than  the  Utah  wools,  and  will  scour 
out  very  white.  In  this  latter  respect  the  Wyoming  wools  are  superior  to  any 
other  grown  west  of  the  Mississippi  River.  The  shortest  wools  grown  in  America 
arc  from  California  and  Texas;  they  are  used  principally  for  felts  and  hats,  though 
they  can  also  be  mixed  in  certain  proportions  with  clothing  wool.  As  the  Terri- 
tory wools  are  grown  mostly  in  dry  climates,  they  will  gain  somewhat  in  weight 
on  being  shipped  to  the  Atlantic  seaboard  and  stored  for  a  few  months.  Utah 
wools  will  gain  about  i%,  Montana  wools  about  }%,  and  Wyoming  wools  about 
i%.  The  wools  from  Ohio  and  other  eastern  States  will  not  gain  anything;  in 
fact,  will  sometimes  show  a  slight  shrinkage.  (American  Wool  and  Cotton  Re- 
porter.) 


WOOL   AND  HAIR  FIBRES.  27 

30  to  40  Ibs.  With  respect  to  the  variation  in  fibres  derived  from 
different  kinds  of  sheep,  Bowman  gives  the  following  classifica- 
tion: 

(1)  Those  sheep  the  fibres  of  whose  wool  most  nearly  approach 
to  a  true  hair,  the  epidermal  scales  being  most  horny  and  attached 
most  firmly  to  the  cortical  structure.     This  class  includes  all  the 
lustrous  varieties  of  wool,  besides  alpaca  and  mohair. 

(2)  Those  where  the  epidermal  scales,  though  more  numerous 
than  in  the  first  class,  are  less  horny  in  structure  and  less  adherent 
to  the  cortical  substance  of  the  fibre.     This  class  includes  most 
of  the  middle- wooled  sheep  and  half-breeds. 

(3)  Those  where  the  characteristics  of  true  wool  are  most 
highly  developed,   such  as  suppleness  of  fibre  and  fineness  of 
texture,  the  epidermal  scales  being  attached  to  the  cortical  sub- 
stance  through  the   smallest  part  of  their  length.     This   class 
includes  all  the  finest  grades  of  sheep,,  such  as  the  merino  and 
crosses  with  it. 


CHAPTER  III. 

THE  CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL  AND    HAIR 

FIBRES. 

i.  Chemical  Constitution. — In  its  chemical  constitution  wool 
is  closely  allied  to  hair,  horn,  feathers,  and  other  epidermal  tissues. 
A  distinction  must  be  made  between  the  fibre  proper  and  the 
raw  fibre  as  it  comes  from  the  fleece.  In  the  latter  condition  it 
contains  a  large  amount  of  dirt,  grease,  and  dried-up  sweat 
which  have  first  to  be  removed  by  the  scouring  process  before 
the  pure  fibre  is  obtained.  Reserving  these  impurities  for  a 
further  discussion  which  does  not  concern  us  at  this  point,  and 
discussing  only  the  fibre  itself,  it  has  been  found  to  consist  of 
five  chemical  elements;  namely,  carbon,  hydrogen,  oxygen, 
nitrogen,  and  sulphur.  Nitrogen  is  an  ingredient  common  to 
both  wool  and  silk,  but  sulphur  is  distinctly  characteristic  of  wool 
and  hair  fibres.  To  show  the  average  amount  of  pure  fibre  to 
be  obtained  from  raw  fleece  wool,  the  following  analysis  by  Chev- 
reul  of  a  merino  wool  is  given: 

Per  Cent. 
Earthy  matter  deposited  by  washing  the  wool  in  water.  .    .  .    26.06 

Suint  or  yolk  soluble  in  cold  distilled  water 32 .  74 

Neutral  fats  soluble  in  ether 8.57 

Earthy  matters  adhering  to  the  fat i .  40 

Wool  fibre 31-23 


These  figures  are  based  on  wool  dried  at  100°  C.;  if  corrected 
for  uir-dry  wool  containing  14  per  cent,  of  moisture,  this  would 
^ive  only  about  27.5  per  cent,  of  pure  fibre.  Of  course,  the 
amount  of  fibre  will  vary  considerably  in  different  <|ualilies  and 
samples  of  wools,  but  this  figure  may  be  taken  as  a  fair  average. 

The  presence  of  nitrogen  in  wool  is  readily  made-  evident  by 

28 


WOOL   AND  HAIR  FIBRES.  29 

simpty  burning  a  small  sample  of  the  fibre,  when  the  character- 
istic empyreumatic  odor  of  nitrogenous  animal  matter  will  be 
observed.  By  heating  wool  in  a  small  combustion  test-tube  it 
will  be  noticed  that  ammonia  is  among  the  gaseous  products 
evolved,  and  can  be  tested  for  in  the  usual  manner.  The  pres- 
ence of  sulphur  in  wool  can  be  shown  by  dissolving  a  sample  of 
the  fibre  in  a  solution  of  sodium  plumbite  (obtained  by  dissolving 
lead  oxide  in  sodium  hydrate),  when  a  brown  coloration  will  be 
observed,  due  to  the  formation  of  lead  sulphide.  On  adding 
hydrochloric  acid  to  the  solution  and  heating,  the  odor  of  sul- 
phuretted hydrogen  will  be  distinctly  noticed.  The  application 
of  this  test  to  show  the  presence  of  sulphur  in  wool  is  sufficient  to 
discriminate  chemically  between  that  fibre  and  those  consisting 
of  silk  or  cotton,  and  also  to  detect  wool  in  admixture  with  other 
fibres.  The  older  methods  of  hair-dyeing  were  based  on  this 
same  reaction,  solutions  of  soluble  lead  salts,  such  as  sugar  of 
lead,  being  applied  to  the  hair,  with  the  result  that  lead  sulphide 
would  be  formed  and  cause  a  dark  brown  coloration.  The  use 
of  such  preparations,  however,  is  dangerous,  as  they  are  liable  to 
cause  lead  poisoning. 

The  presence  of  sulphur  in  wool  may  at  times  be  the  cause  of 
certain  defects  in  the  dyeing  process.  In  neutral  or  alkaline 
baths,  if  lead  is  present,  the  color  obtained  on  the  fibre  will  be 
more  or  less  affected  by  the  lead  sulphide  formed  on  the  wool,  and 
serious  stains  may  be  the  result.  The  presence  of  sulphuric 
acid,  however,  prevents  this,  and  no  staining  of  the  fibre  takes 
place.  Stains  are  sometimes  produced  when  wool  is  mordanted 
with  stannous  chloride,  as  in  the  dyeing  of  cochineal  scarlets,  due 
to  the  formation  of  stannous  sulphide.  Occasionally  woolen 
printed  goods  exhibit  brownish  stains  on  the  white  or  light- 
colored  portions  after  being  steamed.  These  may  be  due  to  slight 
traces  of  copper  or  lead  being  deposited  on  the  cloth  during  its 
manipulation  and  passage  through  the  machines,  and  these  metals 
when  the  wool  is  steamed  form  dark-colored  sulphides  which  cause 
the  stains.  By  locally  applying  a  weak  solution  of  hydrogen 
peroxide  such  discoloration s  may  be  removed  without  injury  to 
the  printed  color. 


30  THE   TEXTILE  FIBRES. 

Chevrcul  recognized  the  fact  that  in  certain  dyeing  operations 
it  was  necessary  to  remove  the  sulphur  from  wool  as  far  as  possible 
in  order  to  obtain  the  best  results.  He  accomplished  this  by 
steeping  the  wool  in  milk  of  lime  and  afterwards  in  a  weak  bath 
of  hydrochloric  acid,  and  finally  washing. 

The  amount  of  sulphur  existing  in  wool  does  not  appear  to  be 
a  very  constant  factor,  but  varies  in  different  samples  of  wool 
from  0.8  to  4  per  cent.  The  manner  in  which  the  sulphur  exists 
in  the  molecular  structure  of  the  fibre  is  by  no  means  clear,  as 
the  majority  of  it  is  readily  removed  without  any  apparent  struc- 
tural modification  of  the  fibre  itself.  According  to  Chevreul, 
the  amount  of  sulphur  in  wool  was  reduced  to  0.46  per  cent,  by 
several  treatments  with  lime-water.  Treatment  with  a  concen- 
trated solution  of  caustic  soda  in  such  a  manner  as  not  to  disinte- 
grate the  fibre  (see  p.  40)  will  remove  as  much  as  84.5  per  cent, 
of  the  sulphur  originally  present  in  the  wool.  On  a  sample  of 
wool  containing  3.42  per  cent,  of  sulphur,  treatment  in  this  man- 
ner left  only  0.53  per  cent,  of  sulphur  in  the  fibre.  This  would 
appear  to  indicate  that  the  sulphur  is  not  a  structural  constituent 
of  the  wool  fibre.  The  fact,  however,  that  the  sulphur  present 
is  not  all  removed  by  even  such  severe  treatment  as  described 
would  also  serve  to  indicate  that  this  element  may  exist  in  wool 
in  two  forms,  the  one  an  ultimate  constituent  of  the  fibre,  and 
the  other,  and  major  part,  as  a  more  loosely  combined  compound. 
The  fact  that  the  amount  of  sulphur  naturally  present  in  wool  is 
by  no  means  constant  would  also  tend  to  support  this  view;  as 
would  also  the  fact  that  the  major  portion  of  the  sulphur  is  so 
readily  split  off  to  form  metallic  sulphides.  On  dissolving  wool 
in  boiling  caustic  soda,  it  does  not  appear  that  all  of  the  sulphur 
is  converted  into  sodium  sulphide,  as  only  about  80  per  cent,  of 
it  can  be  obtained  as  hydrogen  sulphide  when  the  caustic  soda 
solution  is  treated  with  acid.  Probably  the  remainder  of  the 
sulphur  exists  in  the  wool  as  a  sulphonic  acid,  or  some  compound 
of  a  similar  nature. 

In  its  chemical  nature  wool  appears  to  be  a  proteoid,  known  as 
keratin.  As  its  constituents  are  not  rigidly  constant  in  their 
proportions,  we  cannot  assign  to  wool  a  definite  chemical  for- 


WOOL  AMD  HAIR  FIBRES. 


mula.      On   an    average,   its    composition    may    be    taken    as 
follows : 

Per  Cent. 

Carbon 50 

Hydrogen 7 

Oxygen 26-22 

Nitrogen JS"1? 

Sulphur 2-  4 

Bowman  gives  the  following  analyses  of  four  different  grades  of 
English  wool: 


Constituent. 

Lincoln 
Wool. 

Irish 
Wool. 

Northum- 
berland 
Wool. 

South- 
down 
Wool. 

Carbon  

^2  .O 

40.8 

<;o.8 

ei    7 

Hvdrogen 

6  o 

7   2 

72 

:>*•  6 
6  o 

Nitrogen 

18? 

IQ    I 

l8    5 

17    8 

Oxygen 

20  3 

IQ   0 

21    2 

2O    2 

Sulphur         .' 

2.  ^ 

2    o 

2     2 

3  8 

O    2 

I    O 

These  analyses  were  made  of  wool  which  had  been  purified  by 
extraction  with  water,  alcohol,  and  ether. 

The  continued  action  of  boiling  water,  appears  to  decompose 
the  wool  fibre  to  a  certain  extent,  as  both  ammonia  and  hydrogen 
sulphide  may  be  detected  in  the  gases  evolved. 

By  heating  wool  to  a  temperature  of  130°  C.  with  water  under 
pressure,  the  fibre  appears  to  become  completely  disorganized, 
and  on  drying  may  be  rubbed  into  a  fine  powder.  At  higher 
temperature  the  fibre  is  completely  dissolved.  Based  on  this  fact, 
Knecht  has  proposed  a  method  for  the  carbonization  of  wool  in 
mixed  woolen  and  silk  goods,  for  the  purpose  of  recovering  the 
silk,  as  the  latter  is  not  materially  affected  by  this  treatment. 
The  wool  fibre  as  a  whole  does  not  appear  to  be  a  homogeneous 
chemical  compound;  instead  of  being  a  simple  molecular  body 
to  which  a  definite  formula  might  be  given,  it  is  doubtless  com- 
posed of  several  chemically  distinct  substances.  This  is  evi- 
denced by  the  fact  that  the  proximate  constituents  of  wool  are 
by  no  means  constant  in  their  amount ;  furthermore,  certain  of  its 
constituents  are  in  part  removed  by  simply  boiling  the  fibre  in 
water  without  a  structural  disorganization  taking  place.  The 


32  THE   TEXTILE  FIBRES. 

sulphur  content  is  especially  liable  to  fluctuation,  and  is  the  most 
readily  removed  of  the  chemical  elements  of  which  the  fibre  is 
composed;  in  fact,  so  easily  is  some  of  the  sulphur  removed  as  such 
by  various  solvents,  that  it  would  seem  to  indicate  that  this  con- 
stituent existed  in  wool  either  in  the  free  condition  or  in  a  com- 
pound of  exceedingly  unstable  character. 

Schuetzenberger,  by  decomposing  pure  wool  fibre  by  heating 
with  a  solution  of  barium  hydrate  at  170°  C.,  obtained  the  fol- 
lowing decomposition  products : 

Per  Cent. 

Nitrogen  (evolved  as  ammonia) 5.2; 

Carbonic  acid  (separated  as  barium  carbonate) 4.27 

Oxalic  acid  (separated  as  barium  oxalate) 5.72 

Acetic  acid  (by  distillation  and  titration) 3.  20 

Pyrrol  and  volatile  products i  to  i .  50 

fc     47-85 

Proximate  composition  of  fixed  residue,  containing  leu- 
cin,  ty rosin,  and  other  volatile  products 


H  7.69 
N  12. 6 ; 
O  3 

Williams  has  shown  that  by  distilling  wool  with  strong  caustic 
potash  a  large  amount  of  ammonia  was  obtained  in  the  distillate, 
together  with  butylamin  and  amylamin.  Dry  distillation  of 
wool  yields  an  oil  of  a  very  disagreeable  odor,  probably  consist- 
ing of  various  sulphuretted  bases;  also  a  considerable  amount 
of  pyrrol  and  hydrogen  sulphide  gas,  together  with  a  small  amount 
of  carbon  disulphide,  and  traces  of  various  oily  bases. 

The  fatty  and  mineral  matters  present  on  the  raw  wool  fibre 
consist  on  the  one  hand  of  wool  grease  derived  from  the  fatty 
glands  surrounding  the  hair-follicle  in  the  skin,  and  on  the  other 
hand,  of  dried-up  perspiration  from  the  sudorific  glands  in  the 
skin.  The  wool  grease  is  mostly  to  be  found  as  the  external 
coating  on  the  fibre*  which  serves  to  protect  it  from  mechanical 
injury  and  felting  while  in  the  growing  lleece.f  Then  :^  also  a 

*  The  statement  made  in  ><>mr  text-books  that  raw  wool  when  h  !"t  in  tin* 
greasy  condition  is  not  attacked  by  moths  is  erroneous.  The  personal  experi- 
ence of  the  author  has  proved  that  raw  wool  is  as  liable  to  the  depredations  of 
insects  as  washed  and  scoured  wool. 

t  Cotted  fleeCCB  aie  those  fa  which  the  fibres  have  grown  in  and  amongst  each 

other  on  the  >heep'>  lx)dy  so  that  they  form  a  more  or  le>s  perfert  mat  of  wool. 

.ird  or  soft  according  to  the  extent  to  \\hich  the  matting  process 


WOOL   AND  HAIR  FIBRES.  33 

small  amount  of  oily  matter  contained  in  the  medullary  intercellu- 
lar structure  of  the  fibre  which  appears  to  have  the  function  of 
acting  as  a  lubricant  for  the  inner  portion  of  the  fibre,  thus  pre- 
serving its  pliability  and  elasticity.  Wool  grease  does  not  appear 
to  be  a  simple  compound,  but  evidently  consists  of  several  oils 
and  wax-like  compounds. 

Its  chief  constituent  is  cholesterol,  which  appears  to  be  one 
of  the  higher  monatomic  alcohols,  and  is  not  a  glyceride.  Analysis 
shows  it  to  have  the  formula  C^H^OH.  It  is  a  solid  wax-like 
substance  which  very  readily  emulsifies  in  water.  Associated  with 
cholesterol  there  is  also  an  isomeric  body  called  isocholesterol. 
Besides  these  solid  waxes,  wool  grease  also  contains  two  fats 
which  have  been  studied  by  Chevreul  to  some  extent.  These 
are  described  as  follows: 

(a)  Stearerin;  a  neutral  solid  fat,  melting  at  60°  C. ;  contains 
neither  nitrogen  nor  sulphur;  does  not  emulsify  with  boiling 
water,  but  emulsifies  without  saponification  when  boiled  with 
two  parts  of  caustic  potash  and  water;  it  is  soluble  in  1000  parts 
of  alcohol  at  15.5°  C. 

(6)  Elairerin,  a  neutral  fat  melting  at  i5.5°C.;  also  free 
from  nitrogen  and  sulphur;  it  emulsifies  with  boiling  water, 
and  is  saponified  with  caustic  potash;  it  is  soluble  in  143  parts  of 
alcohol  at  15.5°  C. 

The  dried-up  perspiration  adhering  to  the  raw  wool  fibre 
is  also  called  suint.  It  consists  principally  of  the  potash  salts 
of  various  fatty  acids,  and  it  is  soluble  in  water,  wherein  it  differs 
from  wool  grease.  On  extraction  with  water,  suint  will  yield  a 
dry  residue  of  about  140  to  180  Ibs.  for  1000  Ibs.  of  raw  wool. 


has  been  carried  on.  Cotted  fleeces  occur  mostly  in  sheep  which  have  been 
housed;  they  are  seldom  found  in  the  territories  where  the  sheep  run  on  the  range 
and  are  more  exposed  and  hardy.  Cotted  fleeces  indicate  a  low  degree  of  vitality, 
and  many  are  to  be  found  in  fleece  wool  from  states  east  of  the  Mississippi  River. 
They  may  be  caused  by  sickness  or  a  low  state  of  the  blood,  or  they  may  be  found 
in  an  old  sheep  which  is  giving  out  or  is  run  down,  which  contributes  to  the  frowsy 
condition  of  the  wool.  Cotted  fleeces  are  unfit  for  combing  purposes,  as  they 
have  to  be  torn  apart,  and  frequently  they  are  so  dense  and  hard  that  the  fibres 
can  only  be  pulled  apart  by  the  use  of  special  machinery.  Badly  cotted  fleeces 
are  used  frequently  for  braid  purposes. 


34  THE   TEXTILE  FIBRES. 

This  on  ignition  will  give  70  to  90  Ibs.  of  potassium  carbonate 
and  5  to  6  Ibs.  of  potassium  sulphate  and  chloride,  so  that  the 
amount  of  potash  salts  to  be  derived  from  raw  unwashed  wool 
may  be  taken  to  be  about  10  per  cent,  on  the  weight  of  the  wool. 

Besides  the  mineral  matter  existing  in  the  soluble  suint,  there 
is  also  a  small  amount  of  mineral  matter  which  appears  to  form  an 
essential  constituent  of  the  fibre  itself.  It  is  left  as  an  ash  when 
wool  is  ignited,  and  amounts  on  an  average  to  about  one  per  cent., 
the  majority  of  which  is  soluble  in  water  and  consists  of  the  alka- 
line sulphates.  The  following  analysis  by  Bowman  shows  the 
typical  composition  of  the  ash  of  Lincoln  wool: 

Per  Cent. 

Potassium  oxide 31.1 

Sodium  oxide 8.2 

Calcium  oxide 16.9 

Aluminium  oxide 


Ferric  oxide  )  '  ' 

Silica 5.8 

Sulphuric  anhydride 20 . 5 

Carbonic  acid 4.2 

Phosphoric  acid trace 

Chlorin trace 

Sheep's  wool  is  nearly  always  white  in  color,  though  sometimes 
it  may  occur  in  the  natural  colors  of  gray,  brown,  or  black.  The 
coloring-matter  in  wool  appears  to  withstand  the  action  of  alkalies 
and  acids,  though  it  is  not  especially  permanent  toward  light.  It 
appears  to  be  distributed  in  the  fibre  in  quite  a  different  manner 
from  that  of  the  artificially  applied  dyes.  The  natural  coloring-^ 
matter  appears  to  be  contained  particularly  in  the  cells  of  the 
cortical  layer  and  the  marrow  in  a  granular  form,  and  to  occur  to 
a  greater  extent  in  the  medullary  than  in  the  cortical  cells.  In 
fibres  which  are  only  slightly  colored  the  walls  of  the  cells  are 
almost  colorless;  though  when  the  fibre  becomes  very  strongly 
colored  the  cell-walls  also  appear  to  be  impregnated  with  the 
coloring-matter.  In  wools  which  have  been  dyed,  however,  the 
cell-walls  are  nearly  always  uniformly  colored,  in  consequence  of 
which  the  lumen  of  the  fibre  becomes  less  pronounced;  whereas, 
with  naturally  colored  wools,  the  lumen  is  usually  rendered  more 
distinct  through  the  deposit  of  coloring-matter. 


WOOL  AND  HAIR  FIBRES.  35 

2.  Chemical  Reactions. — In  its  chemical  reactions  wool  ap- 
pears to  exhibit  the  characteristics  both  of  an  acid  and  a  base, 
and  no  doubt  it  contains  an  amido  acid  in  its  composition.  The 
presence  of  an  amido  group  is  evidenced  by  the  formation  of 
ammonia  as  one  of  the  decomposition  products  of  wool,  also  by 
the  strong  affinity  of  wool  for  the  acid  dyestuffs,  or  even  of  its 
ability  to  combine  with  acids  in  general. 

Schuetzenberger  has  shown  that  the  products  of  the  hydrolysis 
of  wool  by  baryta-water  are  analogous  to  those  of  albuminoids 
containing  imido  groups;  the  experiments  of  Prud'homme  and 
Flick  also  indicate  the  presence  of  imido  rather  than  amido 
groups  in  wool.  The  fact  that  wool  absorbs  nitrous  acid,  and 
combines  with  phenols,  which  is  supposed  to  indicate  the  pres- 
ence -of  amido  groups,  may  be  explained  by  the  formation  of 
nitrosamines  with  the  imido  groups,  which  would  also  yield  col- 
ored derivatives  with  phenols. 

The  coefficient  of  acidity,  which  is  a  figure  meaning  the  num- 
ber of  milligrams  of  caustic  potash  neutralized  by  one  gram  ot 
substance,  has  been  determined  for  wool,  together  with  a  number 
of  other  albuminoids,  as  follows: 

Wool 57 . o        Albumin 20. 9 

Silk i43-o        Gelatin 28 . 4 

Globulin 101 . 5 

Although  the  amount  of  acid  absorbed  and  neutralized  by  wool 
may  be  thus  quantitatively  determined,  the  amount  of  alkali 
absorbed  cannot  be  so  obtained,  as  wool,  though  it  absorbs  alka- 
lies, does  not  neutralize  them. 

By  treatment  with  concentrated  solutions  of  caustic  soda 
(80°  Tw.)  wool  absorbs  about  50  p~eT  cent,  of  its  weight  of  sodium 
hydrate  from  solution.  Nor  can  this  alkali  be  totally  removed 
from  the  wool  by  subsequent  washing  with  water  alone,  but 
requires  a  treatment  with  acid  for  complete  neutralization.  Wool 
so  treated  exhibits  a  lessened  affinity  for  basic  dyes,  showing  a 
probable  neutralization  to  a  greater  or  lesser  extent  of  its  acid 
component. 

The  amido  acid  of  keratin  has  received  the  name  of  lanu- 
ginic  acid,  and  has  been  prepared  by  dissolving  purified  wool 


36  THE   TEXTILE  FIBRES. 

in  a  strong  solution  of  barium  hydrate,  precipitating  the  barium 
by  means  of  carbon  dioxide,  and  after  filtering,  treating  ilu- 
liquid  with  lead  acetate,  whereby  the  lend  salt  is  obtained.  This 
is  decomposed  by  means  of  hydrogen  sulphide,  and  the  lanuginic 
acid  obtained,  after  evaporation,  as  a  dirty-yellow  substance. 
Its  solution  in  water  yields  colored  lakes  with  the  acid  and  basic 
dyestuffs,  and  also  with  the  various  mordants. 

According  to  Knecht,  lanuginic  acid  possesses  the  following 
properties:  It  is  soluble  in  water,  sparingly  so  in  alcohol,  and 
insoluble  in  ether.  Its  aqueous  solution  yields  highly  colored 
precipitates  with  the  acid  and  basic  dyestuffs;  tannic  acid  and 
bichromate  of  potash  also  give  precipitates.  The  following 
mordants  in  the  presence  of  sodium  acetate  also  give  precipitate^: 
alum,  stannous  chloride,  copper  sulphate,  ferric  chloride,  ferrous 
sulphate,  chrome  alum,  silver  nitrate,  and  platinum  chloride. 
Lanuginic  acid  exhibits  all  the  properties  of  a  proteoid,  and  may 
therefore  be  classed  among  the  albuminoids;  it  is  soluble  in 
water  at  all  temperatures,  and  its  solution  is  not  coagulated. 
With  Millon's  reagent  and  with  the  double,  compound  of  phos- 
phoric and  tungstic  acids,  it  shows  the  characteristic  albuminoid 
reactions.  Knecht  recommends  the  use  of  a  solution  of  wool  in 
barium  hydrate  for  the  purpose  of  animalizing  vegetable  fibres. 
Cotton  so  treated  is  capable  of  being  dyed  with  acid  and  basic 
dyestuffs. 

When  heated  to  100°  C.,  lanuginic  acid  becomes  soft  and 
plastic,  and  the  majority  of  its  colored  lakes  also  melt  at  this 
temperature.  It  is  completely  soluble  in  water  at  all  temper- 
atures and  the  solution  is  not  coagulated  by  boiling.  It  also  gives 
the  characteristic  albuminoid  reactions  with  Millon's  reagent, 
and  the  double  compound  with  phosphoric  and  tungstic  acids. 
Knecht  gives  the  following  analysis  of  lanuginic  acid : 

Per  Cent. 

C 41 .61 

H 7-31 

N 10.26 

S 3-35 

O :,i    H 

93-07 


WOOL   AND  HAIR  FIBRES.  37 

Though  lanuginic  acid  contains  a  notable  amount  of  sulphur  in 
its  composition,  it  is  not  blackened  by  treatment  with  sodium 
plumbite. 

When  treated  with  dilute  acids,  the  wool  fibre  does  not  appear 
to  undergo  any  appreciable  change;  although,  from  the  fact  that 
acids  are  very  readily  absorbed  by  wool  and  very  tenaciously  held 
by  it,  there  is  reason  to  believe  that  some  chemical  combination 
takes  place  between  the  fibre  and  the  acid.  It  can  be  shown,  for 
example,  that  if  wool  be  treated  with  dilute  sulphuric  acid,  all  of 
the  acid  cannot  again  be  extracted  by  boiling  in  water  until  the 
wash  waters  are  perfectly  neutral;  and  wool  thus  prepared  has 
the  power  of  combining  with  the  various  acid  colors  without  the 
necessity  of  adding  any  acid  to  the  dye-bath.  It  is  also  true,  that 
if  wool  which  has  been  treated  with  sulphuric  acid  is  boiled  in 
water,  ammonium  sulphate  is  to  be  found  in  the  solution,  showing 
that  some  chemical  action  has  probably  taken  place  between  the 
acid  and  some  basic  constituent  of  the  wool  fibre.  Hydrochloric 
acid  acts  much  in  the  same  manner  as  sulphuric  acid,  although 
the  amount  permanently  absorbed  by  the  fibre  is  quite  small, 
most  of  the  acid  being  removed  by  boiling  water.  Chromic  acid 
is  also  absorbed  in  like  manner,  and  no  doubt  the  usefulness  of 
bichromates  as  mordants  for  wool  depends  somewhat  on  the 
chemical  combination  between  the  fibre  and  the  chromic  acid. 
With  nitric  acid  wool  behaves  somewhat  differently,  for  unless 
the  acid  be  very  dilute  and  the  temperature  low,  the  fibre  will 
assume  a  yellow  color,  which  is  probably  due  to  the  formation  of 
xanthoproteic  acid.  Formerly  this  yellow  color  was  supposed  to 
be  due  to  the  formation  of  picric  acid,  but  this  view  is  erroneous. 
Nitric  acid  has  a  similar  effect  on  the  skin,  the  yellow  stains  which 
it  produces  being  a  subject  of  common  experience.  If  the 
strength  of  the  acid  is  below  4°  Tw.,  the  yellow  coloration  on 
wool  is  not  very  marked,  and  in  this  manner  nitric  acid  has  been 
largely  employed  as  a  stripping  agent,  especially  for  shoddies. 

•  Richards  has  shown  that  by  the  action  of  nitrous  acid,  wool  is 
diazotized  in  a  manner  similar  to  an  amido  compound,  and  may 
be  developed  subsequently  in  an  alkaline  solution  of  a  phenol, 
giving  rise  to  quite  a  variety  of  shades.  When  wool  is  treated 


38  THE   TEXTILE  FIBRES. 

in  the  dark  with  an  acid  solution  of  sodium  nitrite  (6  per  cent.) 
it  quickly  acquires  a  pale- yellow  color,  rapidly  changing  on  expo- 
sure to  light.  Wool  prepared  in  this  manner  is  turned  brown  by 
boiling  water,  and  caustic  soda  effects  the  same  change,  the  color 
becoming  yellow  again  on  treatment  with  acids.  Stannous  chlo- 
ride in  a  warm  solution  discharges  the  brown  color.  Diazotized 
wool  appears  to  have  an  increased  attraction  for  basic  dyes  and  a 
lessened  affinity  for  the  acid  dyes.  Exposure  to  light  bleaches 
diazotized  wool,  which  is  then  turned  orange  by  alkalies,  and 
not  brown.  The  following  colors  may  be  obtained  by  treating 
diazotized  wool  with  various  phenols  in  alkaline  solution : 

Phenol.  Color.  Reaction  with  H2SO4. 

Resorcin  Orange  Pale  red 

Orcin  Orange  Pale  red 

Pyrogallol                       Yellowish  brown  Orange 

Phloroglucin  Bordeaux  No  change 

a-naphthol                                Red  Black 

/?-naphthol                                Red  Pale  red 

When  dyed  in  connection  with  metallic  mordants,  these  phenol 
colors  are  fast  to  light,  fulling,  acids,  and  boiling  water.  Tin 
mordants  give  yellow  and  orange  shades,  aluminium  orange,  iron 
dark  browns  and  olive  browns,  chromium  and  copper  garnet. 
Wool  treated  with  nitrous  acid  acquires  a  harsh  feel  and  is  non- 
hydroscopic. 

Its  acid  number  is  169,  and  its  iodin  number  4.7,  whereas 
untreated  wool  has  the  numbers  88  and  18.4  respectively.  It 
also  appears  to  contain  less  nitrogen  than  ordinary  wool  (Lidow, 
Chem.  Centr.,  1901,  i,  703). 

Vignon  (Compt.  Rend.,  1890,  No.  17)  has  experimented  on 
the  amount  of  heat  disengaged  by  treating  wool  with  different 
acids  and  alkalies,  with  the  following  results,  using  100  grams  of 
unbleached  wool: 

Reagent.  Calories  Liberated. 

Potassium  hydrate  (normal) 24 . 50 

Sodium  hydrate  (normal) 24 . 30 

Hydrochloric  acid  (normal) 20. 05 

Sulphuric  acid  (normal) 20.90 

These  figures  are  interesting  in  indicating  the  relative  acidity 
and  alkalinity  of  the  wool  fibre. 


WOOL  AND  HAIR   FIBRES.  39 

In  common  with  most  other  organic  substances,  wool  is 
totally  destroyed  by  the  action  of  concentrated  mineral  acids. 

\Yith  organic  acids,  wool  is  usually  reactive,  readily  absorbing 
oxalic,  lactic,  tartaric,  acetic,  etc.,  acids.  Tannic  acid,  however, 
is  an  exception,  and  is  not  absorbed  to  any  extent  by  the  fibre. 
But  if  wool  is  treated  in  a  boiling  solution  of  tannic  acid  and  the 
latter  fixed  in  the  fibre  by  a  subsequent  treatment  in  a  solution 
of  tartaric  emetic  (or  other  suitable  metallic  salt),  it  will  be  found 
that  the  fibre  becomes  altered  in  such  manner  that  it  no  longer 
exhibits  its  normal  affinity  towards  acid,  substantive,  and  mor- 
dant dyes.  Towards  basic  dyes,  however,  the  affinity  of  the 
wool  becomes  considerably  increased  by  reason  of  the  presence  of 
tannin. 

Although  so  resistant  to  the  action  of  acids,  on  the  other  hand, 
wool  is  quite  sensitive  to  alkalies;  so  much  so,  in  fact,  that  a  five 
per  cent,  solution  of  caustic  soda  at  a  boiling  temperature  will 
completely  dissolve  wool  in  five  minutes.  From  this  fact  it  is 
easy  to  understand  why  soaps,  and  scouring  and  fulling  agents 
in  general,  should  be  free  from  appreciable  amounts  of  caustic 
alkalies.  The  weaker  alkaline  salts,  such  as  the  carbonates, 
soaps,  etc.,  are  not  so  destructive  in  their  action,  and  when  em- 
ployed at  moderate  temperatures  they  are  not  regarded  as  dele- 
terious, and  are  largely  used  in  scouring  and  fulling.  With 
respect  to  the  amount  of  caustic  alkali  necessary  to  decompose 
wool,  Knecht  found  that  on  boiling  wool  for  three  hours  with 
three  per  cent,  (on  the  weight  of  the  wool)  of  caustic  soda  the 
fibre  was  not  disintegrated,  but  on  increasing  the  amount  to 
six  per  cent.,  complete  disintegration  took  place  and  the  wool  was 
almost  entirely  dissolved. 

The  action  of  concentrated  solutions  of  caustic  alkalies  on 
wool  is  a  rather  peculiar  one.*  Solutions  of  caustic  soda  of  a 
strength  below  75°  Tw.  will  rapidly  disintegrate  the  fibre,  but 
with  solutions  of  75°-ioo°  Tw.  the  fibre  is  no  longer  disintegrated, 
but,  on  the  other  hand,  increases  from  25  to  35  per  cent,  in  tensile 
strength,  becomes  quite  white  in  appearance,  and  acquires  a 

*  Kertesz,  Fdrber-Zeit.,  ix.  35-36;    Buntrock,  Fdrber-Zeit.,  ix.  69-71. 


40  THE    TEXTILE  FIBRES. 

high  lustre  and  a  silky  scroop.  The  maximum  effect  is  obtained 
by  using  a  caustic  soda  solution  of  80°  Tvv.  and  keeping  the  tem- 
perature below  20°  C.*  The  duration  of  the  treatment  should  not 
be  more  than  five  minutes.  The  addition  of  glycerin  to  the 
solution  of  caustic  soda  renders  the  action  of  the  alkali  more 
effective.  Wool  treated  in  this  manner  may  be  said  to  be  "  mer- 
cerized," though  the  action  of  the  caustic  soda  in  this  case  is 
not  quite  analogous  to  that  in  the  mercerization  of  cotton.  From 
the  decrease  in  the  density  of  the  caustic  soda  solutions  employed, 
it  has  been  shown  that  the  wool  absorbs  a  considerable  amount 
of  sodium  hydrate  from  solution.  Whether  this  is  held  by  the 
•wool  in  true  chemical  combination  has  not  been  ascertained. 
The  treated  wool  contains  but  a  small  amount  of  sulphur  com- 
pared with  that  present  in  the  original  fibre  (see  page  30) ;  analy- 
sis, in  fact,  shows  that  only  about  15  per  cent,  of  the  original  sul> 
phur  remains  in  the  mercerized  wool.  The  dyeing  qualities  of  the 
latter  are  also  different  from  the  original  fibre  in  that  it  absorbs 
more  dyestuff  from  solution  and  hence  yields  heavier  shades. 
Quantitative  tests  have  shown  that  the  increase  in  the  absorption 
of  dyestuff s  is  as  follows: 

Increase, 
Class  of  Dyestuff.  per  cent. 

Basic 12.5 

Acid 20 .  o 

Substantive 25.0 

Mordant 33 . 3 

Mercerized  wool  also  shows  an  increased  absorption  with 
respect  to  solutions  of  various  metallic  salts. 

The  exact  nature  of  the  action  of  caustic  soda  under  the  con- 
ditions given  is  rather  difficult  to  satisfactorily  explain.  Through 
a  microscopic  examination  of  the  treated  fibres  it  appears  that 
the  individual  scales  on  the  surface  of  the  wool  are  more  or  less 
fu>ed  together  to  a  smooth  surface,  which  would  account  for  the 
great  increase  in  lustre.  The  additional  tensile  strength  is  prob- 
ably accounted  for  by  the  same  fact,  the  closer  adhesions  of  the 
scales  giving  a  greater  rigidity  to  the  fibre.  The  volatile  alkalies, 

*  Matthews,  Journ.  Soc.  Chem.  Ind.,  xxi.  685. 


WOOL   AND  HAIR  FIBRES.  41 

such  as  ammonia  and  ammonium  carbonate,  do  not  have  any 
marked  deleterious  effect  on  wool,  especially  at  low  temperatures; 
hence  these  compounds  form  excellent  scouring  materials.  The 
hydroxides  of  the  alkaline  earths,  though  less  violent  in  their  action 
than  the  fixed  caustic  alkalies,  nevertheless  decompose  wool. 
Milk  of  lime,  even  in  the  cold,  abstracts  most  of  the  sulphur,  and 
also  causes  the  fibre  to  become  hard  and  brittle  if  the  action  is 
prolonged;  the  wool  also  loses  its  felting  quality  to  a  considerable 
extent.  Barium  hydroxide,  as  already  noted,  is  used  for  the 
decomposition  of  wool  in  the  preparation  of  lanuginic  acid. 

Towards  other  chemical  reagents  wool  is  much  more  reactive 
than  cotton,  and  either  absorbs  from  solution  or  chemically  com- 
bines with  many  substances.  The  fibre  is  quite  readily  oxidized 
when  treated  with  strong  oxidizing  agents  such  as  potassium 
permanganate  or  bichromate,  becoming  greatly  deteriorated  in 
its  qualities. 

Towards  chlorin  wool  acts  in  a  peculiar  manner;  it  is  com- 
pletely decomposed  by  moist  chlorin  gas,  but  in  weak  solutions 
it  absorbs  a  considerable  amount  of  chlorin  and  is  strangely 
altered  in  its  properties.*  It  becomes  harsh,f  has  a  high  lustre, 
and  acquires  a  silk-like  feel  or  "  scroop,"  at  the  same  time  losing 
its  felting  properties,  though  its  attraction  for  coloring-matters 
in  general  is  largely  increased. \ 


*  Bromin  appears  to  have  a  similar  action  on  wool.  It  is  claimed  to  have 
the  advantages  over  chlorin  in  that  it  does  not  turn  the  material  yellow,  and 
that  in  mixtures  of  dyed  and  undyed  wool  the  former  is  not  attacked.  This 
latter  statement  is  open  to  doubt. 

t  According  to  a  recent  German  patent,  the  harshness  of  chlorinated  wool 
may  be  considerably  lessened  by  working  the  material  first  in  a  solution  of  a  salt 
such  as  citrate  of  zinc  or  acetate  of  iron,  or  of  sodium  stannate  or  aluminate;  this 
is  followed  by  a  second  bath  of  very  dilute  alkali,  after  which  the  goods  are  ex- 
posed  to  the  air.  The  author,  however,  has  not  been  able  to  obtain  any  satisfac- 
tory results  on  testing  this  process. 

t  Chlored  wool  finds  quite  a  number  of  applications  in  practice.  The  process 
is  used,  for  instance,  for  the  purpose  of  imparting  a  silk -like  gloss  to  the  fibre. 
Again,  if  yarns  of  chlored  wool  and  ordinary  wool  are  woven  together  in  pattern, 
and  the  fabric  afterwards  fulled,  since  the  chlored  wool  does  not  felt  it  will  not 
shrink  up  like  the  remainder  of  the  yarn,  and  in  consequence  the  pattern  will  be 
brought  out  with  very  good  effect;  a  great  variety  of  novelties  may  be  produced 
in  this  manner.  Finally,  the  property  of  chlored  wool  to  take  up  more  dyestuff 


42  THE   TEXTILE  FIBRES. 

With  neutral  metallic  salts  wool  does  not  seem  very  reactive, 
as  it  does  not  absorb  them  appreciably  from  their  solutions. 
With  salts,  however,  which  are  acid  in  reaction  and  are  capable 
of  being  easily  dissociated,  such  as  alum,  ferrous  sulphate,  etc., 
the  wool  fibre  possesses  considerable  attraction,  especially  when 
boiled  in  their  solutions. 

With  regard  to  coloring-matters,  wool  is  the  most  reactive 
of  all  the  textile  fibres,  combining  directly  with  acid,  basic,  and 
most  substantive  dyestuffs,  and  yielding,  as  a  rule,  shades  which 
are  much  faster  than  those  obtained  on  other  fibres. 

If  wool  is  left  in  a  warm  place  in  a  moist  condition  so  that 
the  fibre  does  not  have  free  access  to  plenty  of  fresh  air,  it  will 
soon  develop  a  fungoid  growth  or  mildew  in  spots.  This  causes 
the  fibre  to  become  tender  and  eventually  rot.  This  fungoid 
growth  will  develop  without  any  sizing  ingredients  or  other  for- 
eign matter  being  present  on  the  fibre.  It  rapidly  attacks  the 
scales  on  the  surface  of  the  fibre,  and  then  eats  into  the  inner 
substance  of  the  wool.  Under  the  microscope  (see  Fig.  14)  this 
fungoid  growth  appears  as  two  forms:  (a)  Small  elliptical  cells 
which  adhere  to  the  surface  of  the  fibre  and  spread  out  from  it; 
they  seem  to  colonize  especially  at  the  joints  of  the  scales;  (/>)  a 
tree-like  growth  consisting  of  several  cells  joined  together  and 
branching  off  from  one  another;  these  grow  over  the  fibre  as  a 
kind  of  filmy  integument,  and  do  not  appear  to  corrode  the  wool 

than  ordinary  wool,  when  dyed  in  the  same  bath,  is  also  utilized;  and  fabrics  with 
beautiful  two-color  effects  may  be  easily  obtained  in  this  manner  by  weaving  the 
chlored  wool  into  designs  with  ordinary  wool,  and  afterwards  dyeing  with  suitable. 
coloring-matters. 

The  chloring  of  the  woolen  yarn  is  carried  out  in  practice  as  follows:  The 
material  is  well  freed  from  all  greasy  matters  by  a  preliminary  scouring;  this  must 
be  very  thorough,  otherwise  good  results  will  not  be  obtained,  as  tin-  yarn  is  liable 
to  finish  up  very  uneven.  A  steeping  in  hydrochloric  acid  next  takes  place;  the 
solution  should  be  cold  and  have  a  density  of  i  \°  Tw.  The  wool  should  In  left 
in  this  bath  for  twenty  minutes.  It  is  next  passed  into  a  solution  of  bleaching 
powder  standing  at  3°  Tw.,  and  worked  for  ten  minutes;  after  which  it  is  again 
treated  with  the  solution  of  hydrochloric  acid,  and  washed  thoroughly.  It  is 
said  that  sodium  hyj>o<  hlorite  is  better  to  use  than  chloride  of  lime,  and  sulphuric 
acid  is  preferable  to  hydrochloric,  showing  less  tendency  to  turn  the  material 
yellow.  The  yellow  color  due  to  the  chlorin  may  be  removed  by  treatment 
with  sulphurous  a<  id. 


WOOL  AND  HAIR  FIBRES. 


43 


as  rapidly  as  the  first  kind  of  cells.  Mildew  is  especially  apt  to 
develop  on  woolen  material  which  contains  a  small  amount  of 
alkali,  the  alkaline  reaction  probably  being  favorable  to  the 
growth  of  the  fungus. 

Wool  is  more  hygroscopic  than  any  other  fibre,  but  the  amount 
of  moisture  it  will  contain  will  vary  considerably  according  to 


FIG.  14.— Wool  Fibres  Attacked  by  Fungoid  Growth  (Mildew). 

the  humidity  and  temperature  of  the  surrounding  atmosphere. 
Under  average  conditions,  however,  it  will  contain  about  14-18 
per  cent,  of  absorbed  moisture.  The  hygroscopic  quality  of 
wool  is  a  subject  of  considerable  importance  in  the  commercial 
handling  of  this  fibre,  for  the  weight  of  any  given  lot  of  wool  will 
vary  within  large  limits  in  accordance  with  climatic  conditions; 
that  is  to  say,  the  shipment  of  wool  from  one  locality  to  another 
of  different  humidity  and  temperature  will  cause  a  loss  or  gain 


44  THE   TEXTILE  FIBRES. 

in  the  apparent  weight  of  the  material.  So  important  a  factor 
has  this  become  in  the  commercial  relations  between  wool  dealers, 
that  conditioning  houses  for  wool  have  been  established  in  many 
European  centres  for  the  purpose  of  carefully  ascertaining  the 
actual  amount  of  fibre  and  moisture  present  in  any  given  lot  of  wool, 
the  true  weight  being  based  on  a  certain  standard  percentage  of 
moisture,  or  so-called  "  regain."  This  percentage  varies  some- 
what with  the  character  of  the  material  and  also  the  conditioning 
house,  ranging  from  19-16  per  cent.  The  hygroscopic  quality  of 
wool  also  has  an  important  bearing  on  the  spinning  and  finishing 
processes  for  this  fibre,  it  being  necessary  to  maintain  a  definite 
and  uniform  condition  of  moisture  in  order  that  the  best  results 
be  obtained  in  the  spinning  of  yarns  and  the  finishing  of  the 
woven  fabric.  The  wool  fibre  also  appears  to  possess  a  certain 
amount  of  water  of  h  yd  rat  ion,  which  is  no  doubt  chemically 
combined  in  some  manner  with  the  fibre  itself;  for  it  has  been 
observed  that  wool  heated  above  100°  C.  becomes  chemically 
altered  through  a  loss  of  water  at  that  temperature.  This  will 
no  doubt  explain  the  fact  that  air-dried  wool  is  superior  in  quality 
to  that  dried  by  means  of  artificial  heat,  which  usually  signifies  a 
rather  elevated  temperature.  According  to  Persoz,  the  destruc- 
tive action  of  high  temperatures  on  the  wool  fibre  may  be  pre- 
vented by  saturating  the  material  with  a  10  per  cent,  solution 
of  glycerin,  after  which  treatment  the  wool  may  be  exposed  to  a 
temperature  of  140°  C.  without  being  affected.  The  explanation 
of  this  action  is  no  doubt  to  be  found  in  the  fact  that  glycerin 
holds  water  with  considerable  energy,  and  even  at  these  elevated 
temperatures  all  of  the  moisture  originally  present  in  the  wool 
is  not  driven  out  of  the  fibre.  In  order  to  economize  time,  it  is 
sometimes  necessary  to  dry  wool  rather  quickly  by  the  use  of 
suitable  machinery  and  high  temperatures.  \Yhere  a  proper 
regulation  of  the  temperature  is  possible,  the  wet  wool  may  be 
subjected  to  quite  a  high  degree  of  heat  without  injury,  for  the 
fibre  itself  does  not  become  heated  up.  due  to  the  rapid  evapora 
tion  of  the  moisture.  As  the  fibre  becomes  drier,  however,  it  is 
important  that  the  temperature  fall,  SO  that  at  the  end  of  the 
operation,  when  the  wool  has  become  dried  to  its  normal  con 


WOOL   AHD  HAIR   FIBRES. 


45 


tent  of  moisture,  the  temperature  should  be  that  of  the  atmos- 
phere. 

Too  much  importance  cannot  be  attached  to  the  proper  dry- 
ing of  wool  in  all  of  its  stages  of  manufacture,  either  in  scouring, 
dyeing,  washing,  or  finishing.  If  wool  is  overdried,  that  is,  if 
the  moisture  in  it  is  reduced  to  an  amount  much  less  than  that 
which  it  would  normally  contain,  inferior  goods  will  always  be  the 
result,  for  the  intrinsic  good  qualities  of  the  fibre  become  greatly 
depreciated  every  time  such  a  mistake  is  committed. 

The  following  table  shows  the  percentage  of  moisture  in  air- 
dried  wool  and  when  exposed  to  an  atmosphere  saturated  with 
moisture,  as  compared  with  the  same  values  for  other  fibres: 


Fibre. 

Air-dry. 

Saturated. 

Fibre. 

Air-dry. 

Saturated. 

Wool  

8-12 

30—40 

Manila  hemp.  .  .  . 

12.  C 

40 

Silk 

JO—  1  1 

•7Q 

Jute   . 

6 

2?    -I 

Cotton 

6  66 

21 

Flax  

42—  s     7 

1  3    Q—  24. 

Ramie.  .  . 

6    >2 

18  i; 

3.  Conditioning  of  Wool. — In  speaking  of  the  hygroscopic 
quality  of  wool,  it  was  mentioned  that  this  fibre  was  capable  of 
absorbing  a  considerable  amount  of  moisture,  and  that  this  amount 
varied  within  rather  large  limits,  depending  upon  the  conditions 
of  temperature  and  humidity  of  the  air  to  which  it  may  be  exposed. 
It  may  be  readily  understood  from  these  facts,  that  in  the  buying 
and  selling  of  wool  and  woolen  goods  upon  a  basis  of  weight,  the 
question  as  to  how  much  moisture  is  present  becomes  of  great 
practical  importance  in  determining  the  money  value  of  the 
operation.  In  England  and  on  the  continent  of  Europe,  this 
fact  has  been  recognized  for  some  time,  and  there  have  been 
established  at  the  various  European  wool  centres  official  labora- 
tories where  the  percentage  of  moisture  in  raw  wool  or  in  manu- 
factured woolen  material  is  carefully  ascertained,  and  the  sales 
are  based  on  the  actual  amount  of  normal  wool  fibre  contained  in 
the  lot  examined.  These  official  laboratories  are  called  ' '  condi- 
tioning houses, ' '  and  the  process  of  determining  the  amount  of 
moisture  in  the  wool  is  termed  "  conditioning. "  In  the  condi- 
tioning of  wool  the  operation  is  carried  out  as  follows:  Repre- 


46  THE    TEXTILE  FIBRES. 

sentative  samples  are  taken  from  the  lot  under  examination; 
these  are  mixed  together,  and  three  test  samples  of  \  to  i  Ib.  each 
are  taken.  The  test  sample,  after  being  carefully  weighed,  is 
placed  in  the  conditioning  apparatus  and  dried  to  constant  weight 
at  a  temperature  of  io5°-no°C.  (220°  F.).  This  weight  repre- 
sents the  amount  of  dry  wool  fibre  present  in  the  sample,  the  loss 
in  weight  represents  the  amount  of  moisture  the  wool  contained. 
The  amount  of  normal  wool  is  obtained  by  adding  to  the  dry 
weight  of  the  wool  the  amount  of  moisture  supposed  to  be  present 
in  the  air-dried  material  under  normal  conditions  of  humidity  and 
temperature.  The  added  amount  is  termed  "regain,"  and  is 
officially  fixed  by  the  conditioning  house.  This  permissible 
percentage  of  regain  varies  with  the  form  of  the  manufactured 
wool;  the  conditioning  house  at  Bradford,  England,  for  instance, 
has  established  the  following  figures: 

Per  Cent. 

Wools 16 

Tops  combed  with  oil 19 

Tops  combed  without  oil i8£ 

Noils 14 

Worsted  yarns 18 J 

The  conditioning  house  at  Roubaix,  on  the  continent,  allows 
the  following  percentages  for  regain  on  woolen  materials : 

Per  Cent. 

Wools 14! 

Tops i8\ 

Woolen  yarns 17 

The  method  of  calculating  the  amount  of  normal  wool  may 
be  illustrated  by  the  following  example:  A  lot  of  1000  Ibs.  of  loose 
wool  was  submitted  for  conditioning;  ten  samples  of  i  Ib.  each 
were  taken  from  different  parts  of  the  lot;  these  were  mixed 
together  and  three  samples  of  250  grams  each  were  taken  for 
testing.  On  drying  to  constant  weight  the  three  samples  lost, 
respectively,  (i)  18.25  per  cent.,  (2)  18.30  per  cent.,  (3)  18.22  per 
cent.,  making  the  loss  18.26  per  cent.  Hence  in  the  entire  lot 
of  1000  Ibs.  of  wool  there  were  182.6  Ibs.  of  moisture  or  1000— 
182.6=817.4  Ibs.  of  dry  wool.  The  permissible  amount  of 
regain  in  this  case  was  16  per  cent.;  hence  the  normal  amount  of 


WOOL   AND  HAIR  FIBRES. 


47 


wool  would  be  (817. 4X 1  +  817.4=948.2  Ibs.  instead  of  1000 

Ibs. 

The  apparatus  to  be  employed  for  the  conditioning  test  is 
usually  one  of  such  a  construction  as  to  be  especially  adapted 


FIG.  15. — Conditioning  Apparatus. 

for  the  purpose.  The  form  may  differ  somewhat  in  details  with 
different  makers,  but  a  typical  conditioning  oven  may  be  described 
as  follows: 

The  apparatus  consists  of  an  upright  oven  heated  by  a  flame 
placed  in  the  lower  chamber.  An  even  temperature  is  main- 
tained by  so  conducting  the  currents  of  heated  air  that  they  pass 
completely  around  the  inner  chamber  or  oven  containing  the 
sample  to  be  tested.  A  thermometer  projecting  into  the  oven 


\  w 


THE   TEXTILE  FIBRES. 

from  above  is  employed  for  indicating  the  temperature,  and  this 
may  be  maintained  at  the  desired  point  by  a  proper  regulation 
of  the  supply  of  heat.  The  material  to  be  conditioned,  in  what- 
ever form  (as  loose  wool,  yarn,  etc.),  is  placed  in  a  wire  basket 
suspended  from  one  arm  of  a  balance  fixed  outside  and  above  the 


FIG.  1 6. — Another  Form  of  Conditioning  Apparatus. 

oven;  the  weight  of  the  basket  and  its  contents  is  counterpoised 
by  placing  definite  weights  on  a  scale-pan  suspended  from  the 
other  arm  of  the  balance.  As  the  material  diminishes  in  weight 
through  the  volatilization  of  its  moisture,  the  loss  is  noticed  from 
time  to  time  by  removing  the  necessary  weights  from  the  scale-pan 
in  order  to  restore  the  equilibrium  of  the  balance.  When  the 
weight  becomes  constant  after  heating  at  110°  C.,  the  total  loss  is 
recorded,  and  this  figure  represents  the  amount  of  moisture 


WOOL   AND  HAIR  hlBRES.  49 

which  was  originally  present  in  the  material  tested.  The  balance 
is  usually  enclosed  in  a  suitable  case  in  order  to  protect  it  from 
draughts  of  air  whereby  its  sensibility  would  be  impaired. 

Another  form  of  conditioning  apparatus  of  somewhat  differ- 
ent shape  is  shown  in  Fig.  16. 


CHAPTER  IV. 

SHODDY  AND  WOOL  SUBSTITUTES. 

BESIDES  the  natural  varieties  of  wool  which  find  applications 
in  the  textile  industries,  we  have  a  large  quantity  of  regenerated 
wool  employed  as  a  textile  fibre.  This  is  obtained  by  tearing  up 
woolen  rags  and  waste,  converting  it  back  into  the  loose  fibre  and 
spinning  it  over  again,  either  alone,  or  in  admixture  with  varying 
proportions  of  pure  fibre  or  fleece  wool.  This  artificial  wool,  or 
•wool  substitute,  as  it  is  frequently  called,  is  also  obtained  from 
rags  and  waste  containing  wool  and  cotton,  or  even  silk;  the  vege- 
table fibre  being  destroyed  by  chemical  treatment,  leaving  the 
animal  fibre  to  be  extracted  and  used  again.  On  this  account  it 
is  sometimes  known  as  extract  wool.  The  industry  of  converting 
regenerated  fibre  into  yarns  and  fabrics  has  assumed  of  late, 
enormous  proportions,  and  nearly  all  cheap  woolen  goods  contain 
a  high  percentage  of  these  wool  substitutes  in  their  composition. 
Depending  on  its  source  of  production,  this  regenerated  wool  will 
vary  largely  in  its  quality,  and  according  to  its  origin  and  nature 
it  is  classed  under  several  names,  chief  among  which  are  the 
following : 

(a)  Shoddy.     Though  this  name  is  frequently  applied  to  all 
manner  of  regenerated  fibre,  it  is  more  specifically  used  to  desig- 
nate that  which  is  derived  from  all-wool  rags  or  waste  which  have 
not  been  felted,  also  from  knit  goods.     This  yields  the  best  qual- 
ity of  fibre,  the  average  length  of  which  is  about  one  inch.     In 
many  cases  it  is  almost  equal  in  quality  to  a  fair  grade  of  fleece- 
wool,  and  is  used  in  the  production  of  many  high-grade  fabrics. 

(b)  Mungo  refers  to  the  fibre  obtained  from  woolen  material 

5° 


SHODDY  AND   WOOL  SUBSTITUTES.  ,  51 

which  has  been  fulled  or  felted  considerably;  to  disintegrate  the 
rags  the  fibres  must  be  torn  apart,  and  consequently  it  yields 
fibres  of  shorter  staple  and  less  value  than  the  preceding. 

(c)  Extract  wool  is  that  obtained  from  mixed  wool  and  cotton 
rags  and  waste,  and  has  to  undergo  the  process  of  carbonization 
whereby  the  vegetable  fibre  is  destroyed.*  It  is  sometimes  called 
alpaca,  and  varies  much  in  its  length  of  staple  and  other  qualities. 
Besides  these  well-known  varieties  of  regenerated  wool  there  are 
a  number  of  others  to  be  met  with  in  commerce,  such  as  Thibet 
wool,  which  is  usually  obtained  from  light-weight  cloth  clippings 
and  waste.  Cosmos  fibre  is  a  very  low  grade  material,  usually  con- 
taining no  wool  at  all,  being  made  by  converting  flax,  jute,  and 
hemp  fabrics  back  to  the  fibre.  Even  the  short  down  obtained 
in  the  shearing  of  woolen  cloths  is  used;  it  being  employed  as  a 
filler.  The  process  of  using  it  is  called  "  impregnating,"  and  con- 
sists in  fulling  the  short  waste  into  the  cloth  on  the  under  side. 

Woolen  fibres  consisting  of  shoddy,  usually  offer  a  very  char- 
acteristic appearance  under  the  microscope,  sufficient,  at  least,  to 
distinguish  them  from  fibres  of  new  wool.  A  sample  of  shoddy 
generally  shows  the  presence  of  other  fibres  besides  wool,  and 
fibres  of  silk,  linen,  and  cotton  are  frequently  to  be  observed  (Fig. 
17).  Also,  the  colors  of  the  different  woolen  fibres  present  is 
frequently  quite  varied,  so  that  shoddy  usually  presents  a  multi- 
colored appearance  under  th^  microscope.  A  very  striking 
appearance,  also,  is  the  simultaneous  occurrence  of  dyed  and 
undyed  fibres;  the  diameters  of  the  fibres. will  also  vary  between 
large  limits,  the  variation  in  this  respect  being  much  more  than 
with  fresh  wool.  Some  samples  of  shoddy  will  also  show  a  large 
number  of  torn  and  broken  fibres;  and  usually,  the  external 
scales  are  rougher  and  more  prominent. 

It  must  be  borne  in  mind,  however,  that  pure  wool  may  also 

*  This  process  is  generally  carried  out  by  steeping  the  rags  in  a  solution  of 
sulphuric  acid  (6°  Tw.)  at  140°  to  180°  F.,  and  then  drying;  whereupon  the  vege- 
table fibres  are  decomposed  and  are  easily  dusted  out  by  willowing,  whereas 
the  wool  fibres  are  scarcely  affected.  The  excess  of  acid  is  then  removed  by 
treatment  with  soda-ash  and  washing.  The  fibres  obtained  are  sometimes  over 
one  inch  in  length. 


52  THE   TEXTILE  FIBRES. 

show  the  presence  of  small  quantities  of  vegetable  fibres  at  times. 
These  often  arise  from  the  occurrence  of  burrs  (bristly  and  barbed 
seeds  of  various  plants)  in  the  original  fleece.  South  American 
wools  are  especially  liable  to  contain  such  burrs;  in  many  cases 
these  are  incompletely  removed,  and  may  ultimately  appear  even 
in  the  woven  cloth.  This  frequently  explains  the  existence  of 
short  fibres  or  vascular  bundles  of  vegetable  matter  in  cloth. 
Isolated  fibres  of  woody  tissue  and  cotton  may  also  accidentally 


FIG.  17. — Typical  Appearance  of  Shoddy  Fibres  (X25o). 
Showing  fibres  of  various  characters  and  colors. 

creep  in  through  a  variety  of  causes.  According  to  Hohnel, 
samples  of  pure  wool  may  easily  contain  as  much  as  i  per  cent, 
of  vegetable  fibre.  The  latter  authority  also  states  that  the  vege- 
table fibres  of  shoddy,  as  a  rule,  are  removed  by  carbonizing; 
hence  the  absence  of  cotton,  linen,  etc.,  must  not  be  taken  as  a 
criterion  to  distinguish  between  pure  wool  and  shoddy.  When, 
however,  cotton  (always  dyed)  or  cosmos  fibre  occurs  in  at  least 
a  quantity  of  one  per  cent.,  this  may  be  taken  as  a  direct  indica- 
tion of  the  presence  of  shoddy,  as  it  would  scarcely  ever  happen 
that  pure  wool  is  adulterated  with  cotton;  this  only  happens  by 
admixture  with  shoddy-wool.  Undyed  cotton,  unless  present  in 
considerable  amount,  cannot  be  considered  as  a  suspicious  com- 
ponent. 

The  determination  of  the  length  of  staple  is  also  a  rather  unre- 


SHODDY  AND    WOOL   SUBSTITUTES.  53 

liable  indication  as  to  the  presence  of  shoddy,  for  there  are  vari- 
eties of  shoddy-wools  which  are  longer  in  staple  than  many  fleece- 
wools;  and  also  woven  goods,  though  composed  entirely  of 
fleece-wool,  may  show  the  presence  of  a  large  number  of  short 
fibres  caused  by  the  shearing  of  the  surface  of  the  cloth,  and  also 
brought  about  by  tearing  of  the  fibres  in  heavy  pulling. 

Where  woolen  cloth  has  been  impregnated  or  filled  with 
short  fibres  obtained  from  clippings,  such  may  usually  be  recog- 
nized by  teasing  the  sample  out  with  a  stiff  bristle-brush.  Good 
cloth  should  not  yield  over  £  per  cent,  of  clipped  fibres  from  both 
sides.  When  the  amount  of  such  fibres  is  at  all  considerable, 
they  may  be  used  as  serviceable  material  to  test  microscopically 
for  shoddy,  as  they  are  most  likely  to  be  made  up  of  this  character 
of  wool. 

Fine  fleece-wools  hardly  ever  show  the  absence  of  epidermal 
scales  (though  this  is  frequently  the  case  with  coarse  wools); 
hence  if  examples  of  such  fine  wools  are  found  showing  a  lack  of 
epidermis,  it  may  usually  be  taken  as  an  indication  of  shoddy. 

Hohnel,  however,  calls  attention  to  the  fact  that  the  following 
conditions  previous  to  the  manufacturing  process  itself  have  con- 
siderable influence  on  the  good  structure  and  integrity  of  the 
wool  fibre :  badly  cut  staple,  lack  of  attention  in  raising  the  sheep, 
poor  pasturage,  sickness  of  the  animal,  the  action  of  urine,  snow, 
rain,  dust,  etc.,  packing  the  wool  in  a  moist  condition,  rapid 
and  frequent  changes  of  moisture  and  temperature,  the  use  of  too 
hot  or  too  alkaline  baths  in  scouring,  scouring  with  bad  deter- 
gents, etc.  These  influences  may  lead  to  the  partial  removal  of 
the  epidermis,  and  to  the  softening  and  breaking  of  the  ends  of 
the  fibre.  There  must  also  be  considered  the  influence  of  wil- 
lowing,  carding,  combing,  spinning,  weaving,  gigging,  fulling, 
acidifying,  washing,  shearing,  pressing,  etc.,  from  which  it  is 
easy  to  understand  why  even  fleece-wool  may  show  the  entire 
absence  of  epidermis.  Hohnel  also  criticises  other  alleged  char- 
acteristics of  shoddy,  such  as  torn  places  in  the  fibre,  uneven- 
ness  in  diameter,  etc.,  claiming  that  these  can  hardly  be  taken 
as  an  indication  of  shoddy,  because  such  marks  are  often  regu- 
larly present  in  many  fleece-wools.  Most  samples  of  shoddy,  in 


54  THE   TEXTILE  FIBRES. 

fact,  show  scarcely  any  structural  differences  from  ordinary 
fleece-wool.  The  ends  of  shoddy  fibres,  however,  usually  present 
a  torn  appearance;  at  least  there  is  a  great  predominance  of  such 
fibres  in  shoddy,  whereas  in  fleece-wool  this  appearance  is  seldom 
to  be  observed,  the  end  of  the  fibre  being  cut  off  sharply.  The 
appearance  of  the  torn  fibres  may  be  easily  observed  under  the 
microscope;  the  epidermis  being  entirely  torn  away,  as  well  as 
the  marrow  which  is  sometimes  present,  while  the  fibrous  cortical 
layer  is  frayed  out  like  the  end  of  a  brush.  This  appearance  can 
usually  be  rendered  more  distinct  by  previously  soaking  the  fibres 
in  hydrochloric  acid.  Sheared  fibres  are  recognized  by  being 
very  short  and  by  having  both  ends  sharply  cut  off. 

The  color  of  the  fibres  is  also  a  characteristic  appearance  of 
shoddy,  as  the  majority  of  shoddy  is  made  up  of  variously  colored 
wools.  It  is  of  rare  occurrence  that  rag- shoddy  possesses  a  single 
uniform  color.  Hence  if  a  sample  of  yarn,  possessing  a  single 
average  color,  on  examination  reveals  the  presence  of  variously 
colored  fibres,  it  is  almost  a  positive  indication  of  shoddy.  In 
this  connection  it  must  not  be  forgotten,  however,  that  fre- 
quently differently  colored  wools  are  mixed  together  previous  to 
spinning,  to  make  so-called  "  mixes."  As  a  rule,  however,  only 
two  to  three  colors  are  used  together;  therefore  a  purposely  mixed 
yarn  of  this  description  is  not  likely  to  be  confounded  with  a 
shoddy  yarn  where  individual  fibres  of  a  large  number  of  colors 
are  nearly  always  shown. 


CHAPTER   V. 

OTHER  HAIR  FIBRES. 

1.  BESIDES  the  fibre  obtained  from  the  domestic  sheep,  there 
are  large  quantities  of  hair  fibres  employed  in  the  textile  indus- 
tries and  obtained  from  related  species  of  animals,  such  as  goats, 
camels,  etc.     As  these  are  all  more  or  less  utilized  in  conjunction 
with  wool  itself,  and  are  subjected  to  similar  operations  in  manu- 
facturing, it  will  not  be  out  of  place  to  consider  them  at  this  point. 
The   chief   among   these   related   fibres   are   mohair,    cashmere, 
alpaca,  cow- hair,  and  camel's  hair. 

2.  Mohair. — This  fibre  is  obtained  from  the  Angora  goat,  an 
animal  which  appears  to  be  indigenous  to  western  Asia,  being 
largely  cultivated   in  Turkey   and   neighboring  provinces.     The 
fleece  is  composed  of  very  long  fibres,  fine  in  staple,  .and  with  little 
or  no  curl.     The  fibre  is  characterized  by  a  high  silky  lustre. 
Mohair  is  now  grown  to  a  considerable  extent  in  the  Western 
States,    principally    Oregon,    California,    and   Texas,    the    goats 
having  originally  been  imported  from  Turkey;    there  is  also  a 
large  quantity  of  mohair  grown  in  Cape  Colony.     The  principal 
mohair  clips  (1902)  are  as  follows: 

Turkey 8,500,000  Ibs. 

Cape  Colony 7,500,000'   " 

United  States 1,250,000    " 

The  principal  use  of  mohair  is  for  the  manufacture  of  plushes, 
braids,  fancy  dress  fabrics,  felt  hats,  and  linings.  The  charac- 
ter of  fabric  in  which  it  may  be  employed  is  rather  limited  on 
account  of  the  harsh  wiry  nature  of  the  mohair  fibre,  and  the 
fact  that  it  will  not  feh  to  any  degree.  Domestic  mohair  (Ameri- 

55 


56  THE   TEXTILE  FIBRES. 

can)  has  only  about  two- thirds  of  the  value  of  the  foreign  fibre; 
mohair  in  general  has  quite  a  large  amount  of  kempy  fibre  (which 
will  not  dye),  but  the  domestic  variety  contains  about  15  per  cent. 
more  kemp  than  the  foreign,  hence  the  lower  value  of  the  former. 
Another  reason  for  this  lessened  value  is  that  foreign  mohair  always 
represents  a  full  year's  growth  (the  fibres  being  9  to  12  ins.  in 
length),  whereas  a  great  deal  of  domestic  mohair  is  shorn  twice 
a  year.  This  is  especially  true  of  that  grown  in  Texas:  the  hair 
commences  to  fall  off  the  goats  in  that  district  if  allowed  to  grow 
for  the  full  year.  In  judging  of  the  quality  of  mohair,  the  length 
and  lustre  are  of  more  value  than  the  fineness  of  staple.  The  finest 
grades  of  domestic  mohair  come  from  Texas,  that  from  Oregon 
and  California  being  larger  and  coarser.  In  Oregon  the  fleece 
is  grown  for  a  full  year,  and  consequently  the  fibre  is  very  long. 
The  average  weight  of  the  fleece  from  Oregon  goats  is  4  Ibs.,  while 
in  Texas  it  is  only  2\  Ibs.  Foreign  mohair  varies  much  in  quality, 
depending  upon  the  district  in  which  it  is  grown;  as  a  rule,  the 
finer  varieties  are  shorter  in  staple,  the  finest  being  about  9  ins.  in 
length.  Foreign  mohair  can  be  spun  to  as  high  a  count  as  60' s, 
whereas  the  finest  quality  of  domestic  mohair  can  only  be  spun 
to  as  high  as  4o's.  The  coarsest  varieties  of  mohair  are  used  in 
carpets,  low-grade  woolen  fabrics,  and  blankets. 

Microscopically,  the  mohair  fibre  is  possessed  of  the  following 
characteristics:  The  average  length  is  about  18  cm.,  and  the 
diameter  about  40  to  50  /*,  and  very  uniform  throughout  the  entire 
length.  The  epidermal  scales  can  only  be  observed  with  diffi- 
culty, as  they  are  very  thin  and  flat,  though  regular  in  outline. 
They  are  also  very  broad,  a  single  scale  frequently  surrounding  the 
entire  fibre;  the  edge  of  the  scale  is  usually  finely  serrated.  The 
best  grades  of  fibres  show  no  medulla,  but  there  are  usually  to 
be  found  (especially  in  domestic  mohair)  coarse,  thick  fibres  pos- 
sessing a  broad  medullary  cylinder,  thus  resembling  the  structure 
of  ordinary  goat- hair,  from  which,  ho\\v\vr,  they  are  to  be  dis- 
tinguished by  being  more  slender  and  more  uniform  in  their  diam- 
eter. Longitudinally,  the  fibre  exhibits  coarse,  fibrous  striations, 
approximating  the  appearance  of  broad  and  regularly  occurring 
fissures  (see  Fig.  18).  Due  to  the  fact  that  the  surface  scales 


OTHER  HAIR   FIBRES.  57 

lie  very  flat  and  do  not  project  over  one  another,  the  edge  of  the 
fibre  is  very  smooth,  showing  scarcely  any  serrations  at  all,  which 
accounts  for  its  utter  lack  of  felting  qualities.  The  outer  end  of 
the  fibre  is  either  slightly  swollen  or  blunt,  but  never  pointed. 
When  viewed  under  polarized  light  the  fibres  occasionally  show 
the  presence  of  a  medullary  canal,  which  appears  as  a  hollow 
space,  giving  an  illumination  somewhat  resembling  that  of  a 


FIG.  18.— Mohair  Fibres  (X35o). 
Showing  fine,  smooth  scales  and  straight  edges. 

* 

bast  fibre,    and  covering  from   one-fourth   to    one-half    of    the 
diameter. 

3.  Cashmere  is  remarkable  for  its  softness  and  is  much  used 
in  the  woolen  industry  for  the  production  of  fabrics  requiring 
a  soft  nap.  Cashmere  is  the  fibre  employed  in  the  manufacture 
of  the  famous  Indian  shawls.  There  are  two  qualities  of  cash- 
mere wool,  the  one  consisting  of  the  fine,  soft  down-hairs,  and 
the  other  of  long,  coarser  beard-hairs.  The  former  are  ij  to  3^ 
ins.  in  length  and  13  /*  in  diameter,  while  the  latter  are  3^  to  4^  ins. 
in  length  by  60  to  90  a  in  diameter.  The  down- hairs  show 
visible  scales  but  no  definite  medulla,  whereas  the  beard-hairs 
possess  a  well-developed  medulla.  The  cortical  layer  is  coarsely 
striated,  and  shows  characteristic  fissures.  At  the  point  of  the 


THE   TEXTILE  FIBRES. 


fibre  the  epidermal  scales  are  either  entirely  absent,  or  are  so 
thin  as  to  be  scarcely  visible.  The  fibre  is  very  cylindrical; 
the  scales  have  their  free  edge  finely  serrated,  and  the  edge  of 
the  fibre  also  presents  the  same  appearance. 

Besides  mohair  and  cashmere,  the  hair  of  the  ordinary  goat 
is  also  used  at  times.  It  has  the  following  characteristics  (Hohnel)  : 
It  is  white,  yellow,  brown,  or  black  in  color,  and  generally  4  to 
10  cm.  long.  It  consists  almost  entirely  of  wool-hairs,  which, 
like  pulled  wool,  nearly  always  show  the  hair  root.  The  average 
hair  exhibits  the  following  structure  (see  Fig.  19):  At  the  base 


FIG.  19. — a,  Cow-hair;  6,  Goat-hair.     (Hohnel.) 

q,  characteristic  fissures  in  marrow;   m,  marrow  or  medulla  filled  with  air; 
/,  fibrous  fissures;  e,  tile-shaped  scales. 

it  is  about  80  to  90  p  thick;  the  root  is  about  J  mm.  long;  the 
marrow  is  just  visible  at  the  root,  then  rapidly  increases  in  thick- 
ness, so  that  a  few  millimeters  from  the  base  it  is  50  \i  thick, 
where  the  thickness  of  the  hair  amounts  to  80  to  90  /*.  The 
cortical  layer  from  this  point  on  forms  a  very  thin  cylinder.  The 
cross-section  is  round;  the  epidermis  consists  of  broad  scales 
about  15  //  long,  the  forward  edges  of  which  are  scarcely  thickened, 


OTHER  HAIR  FIBRES.  59 

but  Appear  as  if  terminated  by  a  sharp  line;  furthermore  they 
are  not  serrated.  The  medullary  cells  are  thick-walled,  narrow, 
and  flattened.  Towards  the  end  the  hair  is  very  brittle  and 
easily  broken.  Colored  goat-hair  shows  the  presence  of  pigment 
matter  in  all  of  its  tissues;  in  such  fibres  the  marrow  appears 
black. 

4.  Alpaca,  and  its  varieties  Vicuna  and  Llama,  have  the  dis- 
advantage of  being  mostly  colored  from  brown  to  black. 
Though  largely  used  in  South  America  for  the  production  of 
various  fabrics,  they  do  not  find  much  application  in  the  general 
textile  industry.  There  is 'another  product  in  trade  which  goes 
by  the  name  of  vicuna  (French  vicogne),  which  must  not  be 
confused  with  the  true  South  American  fibre,  it  being  simply 
a  trade-name  for  a  mixture  of  cotton  and  wool.  The  name 
alpaca  is  also  given  to  a  variety  of  wool  substitute.  The  South 
American  wools  often  give  rise  to  wool-sorter's  disease  to  those 
handling  them.  This  disease  is  anthrax  and  is  caused  by  the 
presence  of  a  certain  microbe  in  the  fibre.  Wool-sorter's  disease 
is  caused  by  Bacillus  anihracis,  which  may  enter  the  system 
either  by  the  skin  (through  the  medium  of  an  abrasion  or  cut) 
or  by  the  internal  organs,  being  introduced  with  the  food.  In 
the  former  case  it  gives  rise  to  pustules,  which  become  painful 
and  cause  excessive  perspiration,  fever,  delirium,  and  sundry 
disorders.  In  the  latter  case  it  gives  rise  to  the  most  serious 
results,  leading  to  blood-poisoning  and  inflammation  of  the  lungs, 
which  often  prove  speedily  fatal. 

True  alpaca  is  obtained  from  the  cultivated  South  American 
goat,  Auchenia  paco.  It  occurs  in  all  varieties  of  colors  from 
white,  through  brown,  to  black.  The  reddish-brown  and  not 
the  white  variety,  however,  is  the  most  valuable.  Like  other 
goat-hairs,  alpaca  consists  of  two  varieties  of  fibres,  a  soft  :/co!> 
hair  and  a  stiff  beard-hair.  The  wool- hairs  of  the  reddish -V^wn 
variety  are  from  10  to  20  cm.  in  length,  and  from  12  to  -5  u.  in 
diameter  (see  Fig.  20).  The  fibre  is  very  smooth,  the  sec-rations 
on  the  edge  being  faint  and  indistinct;  the  diameter  is  also  very 
uniform,  and  there  are  coarse  brown  longitudinal  striations,  but 
no  medulla.  The  wool-hairs  of  the  white  variety  are  very  dis- 


6o 


THE   TEXTILE  FIBRES. 


tinctly  serrated  on  the  edge,  and  the  fibre  is  not  so  unilormly 
thick.  The  beard-hairs  of  the  brown  variety  are  compara'i vely 
few  in  number,  are  5  to  6  cm.  in  length  and  about  6ou  in  dian  eter, 
and  the  latter  is  very  uniform.  A  very  broad  continuous  medul- 
lary cylinder  is  present,  45  to  50  //  wide;  the  medullary  cells 


FIG.  20. — Fibres  of  Alpaca.     (Hohnel.) 

c,  beard-hair  containing  medulla;  b,  wool-hair  free  from  medulla;  e,  cusp-like 
scales,  thin  and  broad;  k,  granulated  streaks  on  the  fibrous  layer;  m,  medul- 
lary cylinders;  z,  small  medullary  cells. 

are  very  indistinct,  but  are  filled  with  coarse  granules  of  matter. 
The  cortical  layer  shows  occasional  fissures,  and  the  brown 
coloring-matter  is  principally  distributed  through  the  external 
cortical  layer,  though  very  irregularly.  The  beard- hairs  of  the 
white  variety  also  occur  rather  sparingly;  they  are  20  to  30  cm. 
in  length  and  35  ft  in  thickness  at  the  lower  end  and  about  55  /c 
towards  the  upper  end.  The  medulla  is  broad  and  continuous, 
and  nearly  always  filled  with  a  coarsely  granulated  matter  of  a 
gray  color.  The  medulla  consists  of  a  single  row  of  short  cylin- 


OTHER  HAIR  FIBRES.  61 

drical  cells,  but  as  the  walls  are  very  thin,  the  cells  are  to  be 
seen  only  with  difficulty.  The  cortical  layer  is  coarsely  striated 
and  frequently  shows  fibrous  fissures;  the  edge  of  the  fibre  is 
not  sharply  serrated. 

5.  Vicuna  Wool  (or  Vicogne]  is  another  South  American  prod- 
uct obtained  from  Auchenia  viccunia,  the  smallest  of  this  general 
class  of  goat-like  camels.  It  is  not  a  cultivated  animal,  and  is 
evidently  disappearing;  hence  the  fibre  is  not  met  with  in  trade 
to  any  great  extent  at  the  present  time.  It  is  a  soft,  delicate  fibre, 
usually  of  a  reddish-brown  color,  and  much  resembles  alpaca. 
It  also  shows  the  presence  of  a  fine  under-hair  and  a  coarse  upper-  - 
hair;  the  former  is  10  to  20  («  in  diameter,  while  the  latter  is  75  // 
wide.  The  scales  of  the  under-hair  are  very  regular  and  rather 
easy  to  distinguish,  but  generally  no  medulla  is  to  be  seen.  The 
cortical  layer  is  finely  striated  and  frequently  contains  fibrous 
fissures.  The  upper-hairs,  however,  show  a  well-developed 
medulla,  mostly  dark  in  color.  The  fibres  of  the  under-hair  are 
very  uniform  in  diameter  and  about  20  cm.  in  length. 

An  artificial  wool  substitute  also  goes  by  the  name  of  vicuna  or 
vicogne  yarn,  but  bears  no  resemblance  to  the  true  South  Ameri- 
can fibre.  It  consists  principally  of  a  mixture  of  cotton  with 
sheep's  wool,  but  is  frequently  mixed  more  or  less  with  wools 
and  coarse  beard-hairs  of  poor  spinning  qualities  obtained  from 
various  goats  (of  Asia  Minor),  from  camels,  and  from  South 
American  wools.  It  is  of  poor  quality  and  generally  yellowish 
brown  in  color.  It  is  only  used  for  felted  materials  or  for  very 
coarse  fabrics. 

6.  The  Llama  fibre  exhibits  scarcely  any  visible  scales,  but 
has  well-developed  isolated  medullary  cells.  It  also  consists  of 
two  classes  of  fibres,  both  of  which  show  longitudinal  striations. 
The  under-hair  is  20  to  35  /z  in  diameter,  while  the  upper-hair 
averages  150  //.  The  llama  wool  comes  from  the  Auchenia  llama, 
a  cultivated  animal.  The  wool  from  another  variety,  Auchenia 
huanaco,  is  used  to  some  extent  in  South  America,  though  it 
seldom  appears  as  such  in  general  trade.  This  latter  animal  is 
not  cultivated,  but  is  hunted  wild,  and  is  gradually  disappearing. 
Huanaco  and  llama  are  nearly  always  mixed  more  or  less  with 


62  THE   TEXTILE  FIBRES. 

alpaca  and  brought  into  trade  under  the  latter  name.  There  is 
but  little  difference  to  be  found  among  these  three  fibres,  owing 
to  the  close  relationship  of  the  animals  from  which  they  are 
derived,  and  more  especially  as  different  portions  of  the  fleece 
from  all  varieties  of  Auchenia  give  wools  of  entirely  different 
quality  with  respect  to  color,  fineness  of  staple,  and  purity  from 
coarse  stiff  hairs;  and  the  corresponding  portions  from  the  differ- 
ent animals  are  usually  graded  together. 

7.  Camel's  Hair  is  used  to  quite  an  extent  in  clothing  material, 
and  is  characterized  by  great  strength  and  softness.     It  has  con- 
siderable color  in  the  natural  state,  which  does  not  appear  capable 
of  being  destroyed  by  bleaching;    hence   camel's  hair  is  either 
used  in  its  natural  condition  or  is  dyed  in  dark  colors.     There  are 
two  distinct  growths  of  fibre  on  the  camel:  the  under-hair,  which 
is  a  fine  soft  fibre,  largely  employed  for  making  Jager  cloth;   and 
the  upper-  (or  beard-)  hair,  which  is  much  coarser  and  stiff er,  and 
is  mostly  used  for  carpets,  blankets,  etc.     Both  fibres  show  faint 
markings  of  scales  on  the  surface  and  well- developed  longitudinal 
striations.     The  upper-hair  always  exhibits  the  presence  of   a 
well-defined  medulla,  which  is  large  and  continuous,  while  the 
under-hair  either  shows  only  isolated  medullary  cells  or  none  at 
all.     The  diameter  of  the  under-hair  is  from  14  to  28  //,  while 
the  upper-hair  averages  75  /£  (see  Fig.  21).     The  under-hairs  are 
about  ic  cm.  in  length,  are  rather  regularly  waved,  and  are  usually 
yellow  to  brown  in  color;    while  the  others  are  from  5  to  6  cm. 
long,  and  are  dark  brown  to  black  in  color.     The  epidermal  scales 
of  the  latter  are  quite  rough,  which  gives  the  edge  of  the  fibre  a 
saw-toothed  appearance.     The  presence  of  large  spots,  or  motes, 
of  brown  coloring-matter,  especially  in  the  medulla,  is  quite  char- 
acteristic.    These   are   usually   granular   in   form.     The   beard- 
hairs  of  the  camel  are  to  be  distinguished  from  corresponding 
cow-hairs  by  smaller  diameter,  thicker  epidermis,  and  narrower 
medullary  cells  with  thicker  walls,  which  are  generally  darker  in 
color  than  the  enclosed  pigment-matter. 

8.  Cow-hair  is  extensively  employed  as  a  low-grade  fibre  for 
the  manufacture  of  coarse  carpet  yarns,  blankets,  and  a  variety 
of  cheap  felted  goods.     It  is  seldom  used  alone,  however,  on 


OTHER  HAIR  FIBRES.  63 

account  of  its  short  staple.  It  comes  principally  from  Siberia. 
The  diameter  of  cow-hair  varies  from  0.084  to  0.179  mm-  and 
the  length  from  1^—5  cm.  The  fibres  occur  in  a  variety  of  colors, 
including  white,  red,  brown,  and  black.  In  its  microscopic 
appearance  the  surface  of  the  fibre  is  rather  lustreless;  the  ends 
are  very  irregular,  being  blunt  and  divided.  The  medullary  canal 
is  well  marked,  occupying  about  one-half  the  diameter  at  the  base 
and  tapering  towards  the  free  end  where  it  occupies  only  one-fourth 
the  diameter.  Isolated  medullary  cells  are  also  of  frequent 


FIG.  21.  —  Camel's  Hair 


Showing  one  fibre  colored  and  opaque,  with  no  evidence  of  structure  beyond  a 
striated  surface;   and  a  second  fibre  with  well-defined  medullary  cells. 


occurrence.  Cow-hair  (including  also  calf-hair)  nearly  always 
shows  the  hair- root,  as  the  fibres  are  removed  from  the  hide 
by  liming  and  pulling. 

Cow-hair  nearly  always  shows  the  presence  of  three  kinds  of 
fibres : 

(i)  Thick,  stiff  beard-hairs  from  5  to  10  cm.  in  length,  and 
retaining  a  long  narrow  hair  follicle;  above  this  is  the  neck  of 
the  hair,  containing  a  medullary  cylinder  consisting  of  .a  single 
series  of  cells  as  well  as  isolated  medullary  cells.  At  this  part  of 
the  fibre  the  epidermal  scales  are  very  thin  and  broad,  and  the 


64  THE   TEXTILE  FIBRES. 

forward  edges  present  a  serrated  appearance;  the  neck  of  the 
hair  is  about  120  /z  in  thickness.  Above  this  the  hair  rapidly 
increases  to  about  130  //  in  thickness,  and  the  medullary  cylinder 
becomes  broad  (75  /*)  and  consists  of  narrow  brick- shaped  ele- 
ments, arranged  one  on  top  of  the  other.  The  cortical  layer  is 
finely  striated,  the  epidermis  is  indistinct,  and  the  edge  of  the 
fibre  is  smooth.  The  medullary  cells  are  very  thin- walled  and 
contain  a  considerable  amount  of  finely  granulated  matter. 
Towards  the  pointed  end  the  fibre  becomes  colorless,  and  shows 
distinct  fibrous  fissures;  the  medullary  cylinder  disappears,  but 
the  epidermis  is  not  altered.  The  chief  difference  between 
these  hairs  and  the  beard-hairs  of  the  goat  is  that  in  the  former 
the  medullary  cells  consist  of  only  a  single  series,  and  are  very 
thin-walled,  and  are  also  frequently  isolated  from  one  another, 
while  they  are  filled  with  finely  granulated  matter. 

(2)  Soft,  fine,  beard-hairs  possessing  the  same  general  struc- 
ture as  the  foregoing,  but  not  so  thick ;  the  neck  of  the  hair  being 
75  n  in  diameter  and  not  possessing  any  medulla.     Above  this  the 
medullary  cylinder  consists  of  very  thin-walled  cells  arranged  in 
isolated  groups;    the  epidermal  scales  overlap  one  another  and 
are  almost  cylindrical,  are  narrow,  and  with  finely  serrated  edges. 
About  i  cm.  from  the  base  the  medullary  cylinder  becomes  dis- 
continuous and  breaks  up  into  isolated  medullary  cells,  which 
continue  until  the  middle  of  the  fibre  is  reached  where  they  disap- 
pear completely;  towards  the  pointed  end  of  the  fibre,  they  reap- 
pear and  again  become  a  continuous  cylinder,  consisting  of  only 
a  single  series  of  cells,  however.     These  are  well  filled  with  dark 
medullary  substance. 

(3)  Very  fine  soft  wool-hairs,  free  from  medulla,  and  at  most 
only  i  to  4  cm.  in  length,  and  frequently  only  20  jj.  in  thickness. 
The  epidermal  scales  are  rough,  causing  the  edge  of  the  fibre  to 
be  uneven  and  have  a  serrated  appearance.     The  hairs  also  show- 
frequent  longitudinal  fibrous  fissures. 

Calf-hair  has  the  same  general  structure  and  appearance, 
though  there  is  a  greater  amount  of  soft  wool-hairs  present. 

9.  Minor  Hair  Fibres. — Horse-hair  has  a  diameter  of  80  to 
100  //,  and  a  length  of  i  to  2  cm.  (see  Fig.  22).  Like  cow-hair,  it 


OTHER  HAIR  FIBRES. 


also  occurs  in  a  variety  of  different  colors.      Horse-hair  is  more 

lustrous  than  the  foregoing,  however,  and  though  when  viewed 

under  the  microscope  the  ends  of  the  fibre 

are  irregular  and  often  forked,  they  taper  off 

to  points.     The  medullary  cylinder  is  rather 

large,  occupying    about    two-thirds   of   the 

diameter  at  the  base  of  the  fibre,  and  taper- 

ing to  about  one-fourth  of  the  diameter  at 

the  free  end.     The  medulla  consists  of  one 

to  two  rows  of  very  narrow  leaf  -shaped  cells. 

Isolated    medullary  cells    are  of    frequent 

occurrence,   especially  at  the   point.     The 

cortical  layer  frequently  contains  numerous 

short  orifices  or  fissures.      These  remarks 

refer  to  the  body-hairs  of  the  horse;   the 

hairs  of  the  tail  and  mane  are  much  longer, 

reaching  from  several  inches  to  a  foot  or 

more.     They  find  little  or  no   use  in  ordi- 

nary textiles,  but  are  much  used  as  stuffing 

materials  in  the  manufacture  of  upholstery. 
_       .     .  - 

C*t-hair  varies  in  diameter  from  14  to 
34  „,  and  in  length  from  i  to  2  cm.  The 
fibres  occur  in  a  variety  of  colors,  and  have 

,    ,  rr-,,  !  . 

a  good  lustre.  The  ends  are  quite  regular 
and  very  pointed.  The  medullary  canal  contains  a  single 
series  of  regular  cells  occupying  one-half  to  three-fifths  of  the 
diameter  of  the  fibre.  The  cortical  layer  is  well  developed,  and 
its  inner  face  is  grooved  so  as  to  fit  over  the  medullary  cells. 
There  is  a  thin  irregular  epidermis  which  envelops  the  fibre 
(sec  Fig.  23). 

Rabbit-hair  fibres  are  usually  light  brown  in  color,  and  meas- 
ure from  34  to  i2O/£  in  diameter,  and  from  i  to  2  cm.  in  length. 
The  medullary  canal  is  filled  with  several  series  of  cells,  quad- 
rangular in  shape  and  with  thin  walls.  They  are  also  arranged 
in  a  very  regular  manner.  By  careful  observation,  "Spiral  stria- 
tions  may  be  noticed  on  the  finer  fibres.  The  epidermal  scales 
are  very  thick  and  their  forward  edges  terminate  in  a  sharp  point 


FIG.  22.  —  Horse-hair. 

(Hohnel.) 


of  same;  e,  epidermal 

scales;  /,  fibrous  fissures. 


66 


THE    TEXTILE  FIBRES. 


(see  Fig.  24).  Each  scale  is  placed  cornucopia-like  into  the  next 
lower  one,  and  is  drawn  out  into  i  to  3  large  waves.  At  the  base 
of  the  fibre  the  medulla  consists  of  a  single  row  of  cells,  above 


FIG.  23.— Hairs  of  Cat.     (Hohnel.) 

i  to  3,  beard -hairs;  4  to  6,  wool-hairs;  gs,  near  the  end  of  hair;  gm,  middle  of 
hair;  gb,  near  base  of  hair;  7;w,  middle  of  wool-hair;  -ws,  point  of  wool -hair; 
/,  fibrous  fissures;  m,  medullary  cells;  z,  serrated  edge  of  medulla;  r,  tooth- 
like  formation  of  epidermal  scales. 

the  middle  this  increases  to  2  to  4  rows,  and  farther  along  the  fibre 
the  number  of  rows  of  cells  increases  up  to  8,  when  the  hair 

becomes  very  wide.      Like  most  pelt-hairs,  the  fibres  ure  somewhat 


OTHER  HAIR  FIBRES. 


flattened  at  the  base,  and  quite  so  at  their  broadest  part.  The 
cortical  layer  is  only  apparent  towards  the  point  where  the  medulla 
ceases.  The  wool- hairs  of  the  rabbit  are  much  thinner  than  the 


FIG.  24.— Hair  of  Rabbit.     (Hohnel.) 

w,  wool-hairs;  gm,  middle  and  broadest  part  of  beard -hair;  qu,  cross-section  of 
beard-hair;  gb,  base  of  beard -hair;  e,  cusp-like  scales;  i,  medullary  islands; 
m,  n,  medullary  cells  with  granular  contents;  p,  k,  pigment  plate-like  cells. 

above,  the  greatest  thickness  being  about  20  //.  Otherwise  they 
correspond  in  structure  to  that  part  of  the  above  fibre  near  the 
base. 


CHAPTER  VI. 

/SILK:  ITS  ORIGIN  AND  CULTIVATION. 
I.  THE  silk  fibre  consists  of  a  continuous  thread  which  is  spun 
by  the  silkworm.  The  worm  winds  the  fibre  around  itself  in 
the  form  .of  an  enveloping  cocoon  before  it  passes  into  the  chrysalis 
or  pupal  state.  The  cocoon  is  ovoid  in  shape  and  is  composed 
of  one  continuous  fibre,  which  varies  in  length  from  350  to  1200 
meters  (40010  1300  yards),  and  has  an  average  diameter  of  0.018 
mm.  In  the  raw  state  the  fibre  consists  of  a  double  thread 
cemented  together  by  ^f^nveloping  layer  of  silk-glue,  and  is 
yellowish  and  translucent  in  appearance.  When  boiled  off  or 
scoured  these  double  threads  are  separated,  and  the  silk  then 
appears  as  a  single  lustrous  almost  white  fibre.  Unlike  both 
wool  and  cotton,  silk  is  not  cellular  in  structure,  and  is  apparently 
a  continuous  filament  devoid  of  structure.  Hohnel,  however, 
believes  that  the  silk  fibre  is  not  so  simple  in  structure  as  it  is  at 
first  believed.  The  surface  of  the  fibre  frequently  shows  faint 
iations,  which  may  be  rendered  more  apparent  by  treatment 
with  chromic  acid.  Also  by  saturating  the  silk  with  moderately 
concentrated  sulphuric  acid  and  drying,  then  heating  to  80°  to 
100°  C.,  the  fibre  will  be  disintegrated  into  small  filaments,  which 
would  seem  to  indicate  that  it  was  made  up  of  a  number  of  minute 
fibrils  firmly  held  together. 

The  silkworm  is  a  specie  <>l"  caterpillar,  and  though  there  are 
quite  a  number  of  these  which  possess  silk  producing  organs, 
the  number  which  secrete  a  sufficient  quantity  of  the  silk  sub- 
stance to  render  them  of  commercial  importance  is  rather  limited. 

The  true  silkworms  all  belong  to  the  general   (lass  Ispidoplera, 

68 


SILK:    ITS  ORIGIN  AND  CULTIVATION.  69 

or  scale- winged  insects,  and  more  specifically  to  the  genus  Bombyx. 
The  principal  species  is  the  Bombyx  mori,  t>r  mulberry  silkworm, 
which  produces  by  far  the  major  portion  of  the  silk  that  comes 
into  trade.  The  silk  industry  appears  to  have  had  its  origin 
in  China,  and  historically  it  dates  back  to  about  2700  years  B.C. 
In  its  early  history  it  is  said  that  the  art  of  cultivating  the  silk- 
worm and  preparing  the  fibre  for  use  was  a  strictly  guarded 
secret  known  only  to  the  royal  family.  Gradually,  however, 
it  spread  through  other  circles  and  soon  became  an  important 
industry  distributed  universally  throughout  China.  The  Chinese 
monopolized  the  art  for  over  three  thousand  years,  but  during 
the  early  period  of  the  Christian  era,  the  cultivation  of  the 
silkworm  (or  sericulture)  was  introduced  into  Japan.  It  also 
gradually  spread  throughout  central  Asia,  thence  to  Persia  and 
Turkey.  In  the  eighth  century,  the  Arabs  acquired  a  knowledge 
of  the  silk  industry,  which  soon  spread  through  all  the  countries 
influenced  by  the  Moorish  rule,  including  Spain,  Sicily,  and 
the  African  coast.  In  the  twelfth  century  we  find  sericulture 
practised  in  Italy,  where  it  slowly  developed  to  a  national  industry. 
In  France  sericulture  appears  to  have  been  introduced  about  the 
thirteenth  century,  but  it  was  not  until  the  reign  of  Louis  XIV 
that  it  assumed  any  degree  of  importance.  In  more  recent 
times  experiments  have  been  made  on  the  cultivation  of  the 
silkworm  in  almost  every  civilized  country.* 

According  to  the  number  of  the  generations  they  produce  in  a 
year,  the  Bombyx  mori  are  divided  into  two  classes:  the  members 
of  the  one  reproduce  themselves  several  times  annually,  and  are 
termed  polyvoltine ;  their  cocoons  are  small  and  coarse.  The  other 
worms  have  only  one  generation  in  a  year,  and  hence  are  termed 
annual.  The  cocoons  of  the  latter  are  much  superior  to  those  of 
the  preceding.  The  cultivation  of  the  silkworm  starts  with  the 
proper  care  and  disposition  of  the  eggs.  With  the  annual  worms 
there  elapse  about  ten  months  between  the  time  the  eggs  are 
laid  and  their  hatching.  The  hatching  only  takes  place  after  the 

*  Mr.  Samuel  Whitmarsh,  about  1838,  appears  to  have  been  about  the  first 
to  attempt  sericulture  in  America.  He  cultivated  the  Motus  multicaulis  in 
Pennsylvania,  but  the  experiment  proved  to  be  a  failure. 


70  THE   TEXTILE  FIBRES. 

eggs  have  been  exposed  to  the  cold  for  some  time  and  are  sub- 
sequently subjected  to  the  influence  of  heat.{^_When  the  eggs 
are  laid  by  the  silk-moth  they  are  received  on  cloths,  to  which 
they  stick  by  virtue  of  a  gummy  substance  which  encloses  them. 
For  the  first  few  days  they  are  hung  up  in  a  room,  the  air  of  which 
is  kept  at  a  certain  degree  of  humidity — about  semi-saturation. 
Then  comes  a  period  of  hibernation,  during  which  the  eggs  are 
kept  in  a  cool  place;  at  present  artificial  refrigeration  is  resorted 
to  in  many  establishments.  The  period  of  hibernation  lasts 
about  six  months.  After  this  comes  the  period  of  incubation, 
in  which  the  embryo  is  gradually  developed  into  a  worm  and 
the  egg  is  hatched.  The  hatching  usually  takes  place  in  heated 
compartments  in  which  the  temperature  is  carefully  regulated. 
The  period  of  incubation  occupies  about  thirty  days,  though 
this  time  has  been  shortened  considerably  by  certain  artifices, 
such  as  the  action  of  electric  discharges.  Twenty-five  grams 
of  eggs  will  yield  about  36,000  worms  on  hatching.  The  cater- 
pillar, on  first  making  its  appearance,  is  about  3  mm.  long,  and 
weighs  approximately  0.0005  gram.  Its  growth  and  development 
proceeds  with  extraordinary  rapidity,  and  during  its  short  exis- 
tence it  undergoes  a  number  of  very  curious  transformations. 
f  Under  normal  conditions  there  elapse  thirty-three  to  thirty- four 
days  between  the  time  of  the  hatching  of  the  egg  and  the  com- 
mencement of  the  spinning  of  the  cocoon.  During  this  time 
the  worm  sheds  its  skin  four  times,  and  these  periods  of  moulting 
divide  the  life-history  of  the  worm  into  five  periods.  Almost 
immediately  after  being  hatched  the  worms  devour  mulberry 
leaves  with  great  avidity,  and  continue  to  eat  throughout  the 
five  periods,  though  when  about  to  shed  their  skins  they  stop 
eating  for  a  time  and  become  motionless.  The  size  and  weight 
of  the  caterpillars  increase  with  remarkable  rapidity;  during 
the  fifth  period  they  reach  their  greatest  development,  measur- 
ing 8  to  9  cm.  in  length  and  weighing  4  to  5  grams;  and  after 
thus  maturing  they  begin  to  diminish  in  weight.  The  following 
table  by  Vignon  shows  the  relative  weights  of  the  silkworm  during 
the  different  stages  of  its  existence.  The  figures  refer  to  the 
weight  of  36,000  worms: 


SILK:    ITS  ORIGIN  AND   CULTIVATION.  71 

Grams. 

Eggs 25 

Worms  (36,0x30) 17 

First  period  (5  to  6  days) 255 

Second  period  (4  to  5  days) 1,598 

Third  period  (6  to  7  days) 6,800 

Fourth  period  (7  to  8  days) 27,676 

Fifth  period  (n  to  12  days) 161,500 

At  maturity 131,920 

Cocoons 76,250 

Chrysalis  alone 66,300 

Butterflies,  half  of  each  sex 99>865 

Thus  we  see  that  in  less  than  forty  days  the  weight  of  the 
silkworm  increases  almost  10,000  times. 

\Yhen  the  worm  has  reached  the  limit  of  its  growth,  it  ceases 
to  eat,  and  commences  to  diminish  in  size  and  weight.  The  time 
is  now  ready  for  the  spinning  qf  its  cocoon ;  the  worm  perches 
on  the  twigs  so  disposed  to  receive  it  and  exudes  a  viscous  fluid 
from  the  two  glands  in  its  l^dy  wherein  the  silk  secretion  is 
formed.  The  liquid  flows  thrqugh  two  channels  in  the  head  of 
the  worm,  into  a  common  exk-tube^  where  also  flows  the  secre- 
tion of  two  other  symmetrically  situated  glands  which  cements 
the  two  threads  together.  Consequently  the  thread  of  raw 
silk  is  produced  by  four  glands  in  the  worm;  the  two  back  ones 
secrete  the  fibroin  which  gives  the  double  silk-fibre,  while  the 
two  front  glands  secrete  the  silk-glue  or  sericin  which  serves  as  an 
integument  and  cementing  substance.  On  emerging  from  the 
spinneret  in  the  head  of  the  worm,  the  fibre  coagulates  on  con- 
tact with  the  air. 

The  worm  weaves  this  thread  around  itself,  layer  after  layer, 
until  the  cocoon  or  shell  is  gradually  built  up.  It  requires  about 
three  days  for  the  completion  of  the  cocoon.  After  finishing  the 
winding  of  its  cocoon,  the  enclosed  silkworm  undergoes  a  remark- 
able transformation,  passing  from  the  form  of  a  caterpillar  into 
an  inert  chrysalis  or  pupa,  from  which  condition  it  rapidly  devel- 
ops into  a  butterfly,  which  then  cuts  an  opening  through  the 
cocoon  and  flies  away.  As  the  integrity  of  the  cocoon-thread 
would  be  destroyed  by  the  escape  of  the  butterfly,  and  hence 
lose  much  of  its  value,  it  is  desirable  that  the  development  of  the 
chrysalis  be  stopped  before  it  proceeds  too  far,  and  this  is  accom- 


: 


THE   TEXTILE  FIBRES. 


plished  by  killing  it  by  a  heat  of  70  to  80°  C.  or  by  live  steam. 
The  cocoons  at  this  stage  weigh  from  1.25  to  2.5  grams  each, 
and  of  this  15  to  16  per  cent,  is  silk  fibre.  Of  this  amount, 
however,  onlv^JHa  10  per  cent,  is  available  for  silk  filaments,  the 
remainder,  6  to  7  per  cent.,  constituting  waste  and  broken  threads, 
and  is  utilized  for  spun  silk.*  As  to  the  thickness  of  the  filaments 
of  silk  in  the  cocoon,  Haberlandt  furnishes  the  following  data: 


Species. 

Exterior  Layer 
of  Cocoon. 

Middle 
Layer. 

Interior 
Layer. 

Yellow  Milanais  

0.030  mm. 

0.040  mm. 

0.025  mm- 

Yellow  French 

o  02^     " 

O    O3s       " 

o  02?     " 

Green  Japan  

0.030     " 

o  .  040    ' 

O.O2O      ' 

White  Japan 

o  020     ' 

o  030    " 

o  'oi  7     " 

Bivoltin  worms 

O    O2Z      " 

o.o^s;     " 

O.O2O      " 

*  There  are  several  different  varieties  of  waste  silk,  as  follows: 

1.  The  refuse  obtained  in  raising  the  silkworm,  called  Watt  silk  in  commerce. 
Owing  to  the  scientific  methods  of  silk-culture  in  Europe,  the  amount    obtained 
from  this  source  is  very  small.       China,  however,  exports  a  large  amount  yearly. 
This  material  contains  about  35  per  cent,  of  pure  silk,  and  is  the  poorest  grade 
of  waste  silk  on  account  of  its  irregularity. 

2.  The  irregularly  spun  and  tangled  silk  on  the  outside  of  the  cocoon,  called 
floss  silk  or  Frisons.      It  comprises  from  25  to  30  per  cent,  of  the  entire  cocoon, 
and  is  valuable  owing  to  its  purity  and  fine  quality. 

3.  The-residue  of  the  cocoon  after  xeeling;    this  forms  an  inner  parchment-like 
skin,  and  in  commerce  goes  under  the  name  of  ricotti,  wadding,  neri,  Galettame, 
Basinetto,  etc. 

4.  Cocoons  imperfect  from  various  causes,  such  as  being  punctured  by  the 
worms,  becoming  spotted  by  pupa  breaking,  etc.      These  are  known  as  cocons, 
perces,  piques,  tarmate,  rugginose,  etc.      It  forms  a  valuable  material  for  floss 
silk  spinning.     The  be*st  grades  contain  75  to  85  per  cent,  pure  silk,  and    the 
average  is  about  65  per  cent. 

5.  Trouble  cocoons,  which,  in  spite  of  the  difficulty  in  reeling,  were  formerly 
used  for  special  purposes.     Now  such  cocoons  are  converted  into  waste  which 
is  known  as  Strussa. 

6.  Waste  obtained  in  reeling  the  cocoons,  known  asJEfjsonnets. 

7.  A  great  variety  of  wild  silks,  which,  for  the  most  part,  cannot  be  reeled, 
and   are,   therefore,   first  converted  into  waste.     A   large   quantity  of  wild  silk, 
even  though  it  can  be  reeled,  is  torn  up  for  waste. 

8.  Waste  made  by  reeling,  spooling,  and  other  processes  of  working  silk. 
SUk_jhoddy,  resembles  wool  shoddy  in  origin,  consisting  of  recovered  fibres 

from  manufactured  silk  goods.  It  nearly  always  contains  isolated  fibres  of  both 
wool  and  cotton,  and  frequently  mixtures  of  difiVrc-nt  kinds  of  silk.  There  may 
also  occur  boiled-off,  soupled,  and  raw  silk,  and  mixtures  of  organzine  and  spun 
alk.  Different  colors  are  also  usually  present.  The  fibres,  as  a  rule,  are  quite 


SILK:    ITS    ORIGIN  AND  CULTIVATION. 


73 


The  double  silk  fibre  as  it  exists  in  the  cocoon  is  known  as  the 
bave,  and  the  single  filaments  are  called  brim. 

The  size  of  the  single  silk  filament  as  it  comes  from  the  cocoon 
averages  2\  deniers.*  The  following  table  gives  the  approximate 
size  of  filaments  of  mulberry  silk  from  different  countries: 


Weight  in 

500  Meters 

in  Deniers 

in  Milligr. 

Spain.              .  .              

?  o 

163 

Frnnrp^j^^ 

2.6 

38 

Italv^PW  

2.4 

128 

Syria^ 

2    -I 

128 

Caucasus  ...         .  .              . 

2     3 

I2C 

Brousse  .... 

2    2 

117 

Tapan.  . 

2     I 

IJ  7 

j«pc*i 

China  

2    O 

AiJ 

1  08 

Bengal 

I    2 

64 

2.  Wild  Silks. — Besides  the  Bombyx  mori,  or  mulberry  silk- 
worm, there  are  other  associated  varieties  of  caterpillars  which 
also  produce  silk  in  sufficient  quantity  to  be  of  considerable 
commercial  importance.  Due  to  the  fact  that  such  silkworms 
are  not  capable  of  being  domesticated  and  artificially  cultivated 
like  the  mulberry  worms,  the  silk  obtained  from  them  is  called 
wild  silk.  Of  this  latter  there  are  several  commercial  varieties, 
of  which  the  most  important  are  here  given. 

short,  being  about  a  centimeter  in  length.     Due  to  these  components,  silk  shoddy 
is  comparatively  easy  to  recognize  under  the  microscope. 

*  The  fineness  or  size  of  the  silk  thread  is  expressed  by  a  number  known  as 
titre  (in  French)  or  titolo  (in  Italian);  this  gives  the  number  of  units  of  certain 
weight  (denier)  a  skein  of  certain  length  will  weigh.  Several  different  standards 
are  in  use  at  the  present  time,  among  which  are  the  following: 


Weight  in 
Milligrams. 


Length  in 
Meters. 


Denier  (legale) o .  05  450 

Denier  milano 0.051  476 

Denier  turino 0.0534  476 

Old  denier  Lyonese 0.0531  476 

New  denier  Lyonese 0.0531  500 

Denier  international 0.05  500 

The  titre  is  usually  expressed  in  the  form  of  a  fraction,  representing  limits  of 

variation,  as  all  skeins  are  not  of  absolutely  the  same  size.     A  silk  marked  18/20, 

for  instance,  would  mean  that  it  varied  from  1 8  to  20  deniers. 


74  THE    TEXTILE  FIBRES. 

Anthercea  yama-mai,  a  native  of  Japan,  is  a  green-colored 
caterpillar  which  feeds  on  oak-leaves.  Its  cocoon  is  large  and 
of  a  bright  greenish  color.  The  silk  bears  a  close  resemblance 
to  that  of  the  Bombyx  tnori,  but  is  not  as  readily  ,dyed  and  bleached 
as  the  latter. 

AnlJiercea  pernyi  is  a  native  of  China;  besides  growing  wild, 
it  has  been  domesticated  to  some  extent.  This  worm  also  feeds 
on  oak- leaves,  but  is  of  a  yellow  color.  Its  cocoon  is  quite  large, 
averaging  over  4  cm.  in  length,  and  is  of  a  yellowish  to  a  brown 
color. 

Anthercea  assama  is  a  native  of  India;  it  gives  a  large  cocoon 
over  45  mm.  in  length. 

Anthercea  mylitta  is  another  Indian  variety,  and  furnishes 
the  so-called  tussah  silk,  though  this  term  has  also  been  applied  in  a 
general  manner  to  all  varieties  of  wild  silk.  The  worms  feed  on 
the  leaves  of  the  castor-oil  plant,  and  give  very  large  cocoons, 
reaching  50  mm.  in  length  and  30  mm.  in  diameter.  The  color 
varies  from  a  grey  to  a  deep  brown. 

Another  variety  of  silkworm  which  is  to  be  found  both  in 
Asia  and  America  is  the  Attacus  ricini;  it  gives  a  very  white 
and  good  quality  silk,  the  production  and  value  of  which  is  in- 
creasing every  year.  A  species  of  this  class,  known  as  Attacus 
atlas,  is  perhaps  the  largest  moth  known;  it  spins  open  cocoons 
and  gives  the  so-called  Fagara,  or  Ailanthus,  silk. 

Wild  silks  are  much  more  difficult  to  unwind  from  the  cocoons 
than  that  of  the  mulberry  silkworm.  The  silk  is  also  much 
darker  in  color;  it  also  has  less  strength  and  elasticity,  and  is 
much  more  difficult  to  dye  and  bleach. 

Tussah  (or  tussur)  silk  (as  well  as  other  wild  silksj  is  chiefly 
cmplcyed  for  making  pile-fabrics,  such  as  velvet,  plush,  and 
imitation  sealskin. 

3.  The  Microscopical  and  Physical  Properties  of  Silk. — Under 
the  microscope  raw  silk  exhibits  an  appearance  which  readily 
distinguishes  it  from  the  textile-  fihro.  Il  is  seen  as  a  smooth  struc- 
^  turele»  filament,  very  regular  in  diameter  and  very  transparent. 
The  two  brins  in  the  bave  of  raw  silk  give  beautiful  colors  with 
polarized  light  when  examined  microscopically.  The  sericin 


SILK:    ITS  ORIGIN  AND   CULTIVATION.  75 

coating,  however,  appears  to  have  no  such  action.  The  latter, 
being  hard  and  brittle,  on  bending  develops  transverse  cracks 
which  are  very  apparent  under  the  microscope. 

The  fibre  of  Bombyx  mori  is  only  rarely  striated  longitudinally, 
and  when  such  striations  do  appear  they  always  run  parallel  to 
the  axis  of  the  fibreA  When  treated  with  dilute  chromic  acid 
very  fine  striations  are  caused  to  appear.  Wild  silks  often  show 
fibres  which  are  twisted  on  their  axes,  and  the  layer  of  gum  is 
usually  more  or  less  granular.  Anther aa  mylitta  shows  rather 
frequent  oblique  striations,  and  does  not  exhibit  much  play  of 
color  with  polarized  light.  This  latter  characteristic  is  also  true 
of  Antheraa  yama-mai.  The  other  silks  give  colors  with  polar- 
ized light  very  nicely.  Silk  fibres  are  colored  a  deep  red  with 
alloxanthin;  fuchsin  also  gives  a  red  color.  On  treatment 
with  sugar  and  sulphuric  acid,  silk  is  first  colored  a  rose-red  and 
then  dissolves;  hydrochloric  acid  gives  a  violet  color  and  then 
dissolves  the  fibre.  lodin  colors  the  fibres  yellow  to  reddish 
brown. 

Carded  silk,  which  has  been  worked  up  from  imperfect  cocoons, 
etc.,  can  usually  be  recognized  under  the  microscope  by  the  irreg- 
ula'f  and  torn  appearance  of  its  external  layer  of  gum. 

The  inner  layers  of  the  cocoon  consist  of  a  yellow  parchment- 
like  skin,  and  when  examined  under  the  microscope  exhibit  a 
matrix  of  sericin,  in  which  numerous  double  fibres  are  imbedded, 
usually  very  much  fattened  in  cross-section  (Fig.  25,  a).  These 


(a) 

FIG.  25. — Cross-sections  of  Silk  Fibre. 

a,  from  inner  part  of  cocoon;  b,  from  middle  layers  of  cocoon;  c,  from  outer  part 
1     of  cocoon;  /,  fibre  of  fibroin;  5,  layer  of  sericin. 

inner  layers,  of  course,  are  not  capable  of  being  reeled  with  the 
rest  of  the  cocoon,  and  are  used  for  waste  silk.  The  cross-sec- 
tions of  the  fibres  from  the  middle  portion  of  the  cocoon,  con- 


76  THE   TEXTILE  FIBRES. 

stituting  the  reeled  silk,  are  much  more  rounded  in  form  and 
surrounded  with  a  thinner  layer  of  sericin  (see  Fig.  256).  The 
fibres  of  the  outer  part  of  the  cocoon,  also  utilized  for  waste  silk, 
exhibit  a  rather  irregular  cross-section  (see  Fig.  2$c). 

When  raw  silk  is  examined  under  the  microscope  it  will  be 
seen  that  the  appearance  is  by  no  means  regular,  owing  to  the 
broken  and  torn  surface  of  sericin  which  surrounds  the  fibre  (see 


FIG.  26.— Fibres  of  Raw  Silk  (Xsoo). 
Showing  the  double  filament  and  the  irregular  coating  of  silk-glue. 

Fig.  26).  Frequently,  the  two  filaments  of  fibroin  are  distinctly 
separated  from  one  another  for  considerable  distances,  the  inter- 
vening space  being  filled  in  with  sericin.  Occasionally,  the  layer 
of  sericin  is  seen  to  be  entirely  absent,  having  been  removed  by 
breaking  or  rubbing  off.  The  sericin  layer  also  shows  frequent 
transverse  fissures,  which  are  merely  cracks  caused  by  the  break- 
ing of  the  sericin  in  the  bending  or  twisting  of  the  fibre.  Creases 
and  folds  in  the  sericin,  as  well  as  irregular  lumps,  are  also  of 
frequent  occurrence.  All  of  these  markings  are  in  no  wise  struc- 
tural, and  only  occur  in  the  sericin  layer.  At  times  the  fibroin 
fibre  exhibits  structural  changes  in  places,  such  as  discontinua- 
tions; but  these  only  occur  in  defective  and  unhealthy  silk,  and 
give  rise  to  weak  places.  These-  arc  caused  by  the  fibroin  not 
being  secreted  by  the  gland  with  sufficient  rapidity. 


SILK:    ITS  ORIGIN  4ND  CULTIVATION. 


77 


The  microscopic  appearance  of  the  wild  silks  is  very  different 
from  that  of  the  Bombyx  mori.  The  fibres  are  very  broad  and 
thick,  and  in  cross-section  are  very  flat,  and  often  triangular  in 
outline.  Longitudinally,  they  show  very  distinct  striations,  and 
peculiar  flattened  markings,  usually  running  obliquely  across  the 
fibre,  and  in  which  the  striations  become  more  or  less  obliterated. 


FIG.  27.— Wild  Silks. 

A,  view  of  narrow  side;   B,  view  of  broad  side;  C,  cross-sections;  D,  cross- 
section  of  double  fibre;  cr,  cross-marks  on  fibre. 

These  cross-markings  are  caused  by  the  overlapping  of  one  fibre 
on  another  before  the  substance  of  the  fibre  had  completely 
hardened;  in  consequence  of  which,  these  places  are  more  or  less 
flattened  out  (see  Fig.  27).  The  striated  appearance  of  wild  silk 
is  evidence  that  structurally  the  fibre  is  composed  of  minute  fila- 


THE   TEXTILE  FIBRES. 


ments;  in  fact,  the  latter  may  readily  be  isolated  by  maceration 
in  cold  chromic  acid.  According  to  Hohnel,  these  structural 
elements  are  only  0.3  to  i  5  ,«  in  diameter;  they  run  parallel  to 
each  other  through  the  fibre,  and  are  rather  more  dense  at  the 


FIG.  28.— Tussah  Silk  (X340).     (Hohnel.) 

Ay  view  of  narrow  side;  B,  view  of  broad  side;  C,  flat  surface  of  single  fibre  show- 
ing two  thin  cross-marks  at  i  and  2;  /,  air  canals;  g,  fibrillae;  D,  cross- 
section;  *,  inner  layers;  r,  denser  marginal  layers. 

outer  portion  of  the  fibre  than  in  the  inner  part  (see  Fig.  28). 
Besides  the  fine  striations  on  the  fibres  of  wild  silk  caused  by 
their  structural  filaments,  there  are  also  to  be  noticed  a  number 
of  irregularly  occurring  coarser  striations.  These  latter  appear 
to  be  due  to  air- canals,  or  spaces  between  the  filaments  of  the 
fibre  (see  Fig.  29). 


SILK:    ITS  ORIGIN  AND   CULTIVATION.  79 

Hohnel  is  of  the  opinion  that  there  is  really  no  difference 
in  kind  between  the  structure  of  wild  silk  and  that  of  cultivated 
silk;  that  is  to  say,  the  fibroin'fibre  of  the  latter  is  also  composed 
of  structural  filaments,  only  they  fuse  into  one  another  in  a  more 
homogeneous  manner  on  emerging  from  the  fibroin  glands, 
thus  rendering  it  more  difficult  to  recognize  them  superficially. 


B 


FIG.  29.— Cross-section  of  Wild  Silk.     (Hohnel.) 

Ay  diagramatic  drawing  of  section;  *,  air-space;  g,  ground  matrix;  /,  fibrillse; 
r,  marginal  layer;  B,  end  of  fibre  of  tussah  silk  swollen  in  sulphuric  acid; 
C,  cross-section  of  fibre  of  tussah  silk  swollen  in  sulphuric  acid. 

This  view  is  upheld  somewhat  by  the  fact  that  a  slight  striated 
appearance  may  be  noticed  when  the  silk  fibre  is  macerated  in 
chromic  acid  solution.  This  apparent  structure  of  the  silk  fibre, 
however,  may  also  be  due  to  another  cause.  If  a  plastic  glutinous 
mass  (such  as  melted  glue,  for  instance)  be  pulled  out  into  the 
form  of  a  thread  and  allowed  to  harden,  it  will  be  found  to 
exhibit  the  same  striated  structure  as  the  silk  fibre;  and  this 
structure  will  be  more  apparent  if  the  thread  is  pulled  out  and 
hardened  more  rapidly.  The  liquid  fibroin  in  the  glands  of 


8o 


THE   TEXTILE  FIBRES. 


the  worm  is  a  plastic  glutinous  mass  analogous  to  melted  glue, 
and  is  pulled  out  into  the  form  of  a  thread  by  the  action  of  the 
worm  in  winding  its  cocoon;  hence  it  would  be  natural  to  expect 
a  striated  structure  similar  to  that  observed  in  the  thread  of 
glue.  Thus,  it  is  possible  to  account  satisfactorily  for  the  struc- 
ture of  the  silk  fibre  in  a  perfectly  natural  manner,  without  having 


FIG.  290. — Showing  Different  Stages  in  Growth  of  Silkworm. 

A,  silkworm  in  fifth  period,  full  size;  5,  moth  or  butterfly;  C,  chrysalis  or  pupa; 

•£*>  eggs  of  moth;  E,  diagram  snowing  cocoon  and  method  of  winding. 

recoup  to  a  very  doubtful  organic  process  in  the  formation  of 
the  £#re,  such  as  is  supposed  to  be  the  case  by  Hohnel. 
J  Raw  silk  is  quite  hygroscopic,  and  under  favorable  circum- 
stances will  absorb  as  much  as  30  per  cent,  of  its  weight  of  moist- 
ure, and  still  appear  dry.  It  is  therefore  customary  to  determine 
the  amount  of  moisture  in  each  lot  at  the  time  of  sale.  This 
is  called  conditioning,  and  is  usually  carried  out  in  official  labora- 
tories. The  amount  of  moisture  which  is  legally  permitted  is 
1 1  per  cent. 


SILK:   ITS  ORIGIN  AND   CULTIVATION 


81 


Being  a  bad  conductor  of  electricity,  silk  is  readily  electrified 
by  friction,  which  circumstance  at  times  renders  it  difficult  to 
handle  in  the  manufacturing  processes.  The  trouble  can  be 
overcome  to  a  great  extent  by  keeping  the  atmoshpere  moist. 

The  most  striking  physical  property  of  silk,  perhaps,  is  its 
high  lustre.  The  lustre  only  appears  after  the  silk  has  been 
scoured  and  the  silk-gum  removed.  The  lustre  of  silk  is  affected 
more  or  less  by  the  various  operations  of  dyeing  and  mordanting, 
and  especially  when  the  silk  is  heavily  weighted.  After  dyeing, 


FIG.  296. — Showing  Methods  of  Reeling  the  Silk  Fibre  from  the  Cocoon. 

especially  in  the  skein  form,  silk  usually  undergoes  what  is  termed 
a  lustring  operation,  which  consists  generally  in  stretching  the 
hanks  strongly  by  twisting,  and  simultaneously  steaming  under 
pressure  for  a  few  minutes.  This  process  seems  to  bring  back 
to  the  dyed  silk  its  lustre  to  a  considerable  extent.  The  lustre  is 
also  considerably  affected  by  the  method  of  dyeing  and  the 
chemicals  employed  in  the  dye-bath;  it  has  been  found  that 
the  addition  of  boiled-off  liquor  (the  soap  solution  of  sericin 
•obtained  in  the  degumming  of  raw  silk)  to  the  dye-bath  has 
the  result  of  preserving  the  lustre  of  the  dyed  silk  better  than 
anything  else,  and  in  consequence,  boiled-off  liquor  is  nearly 
ahvays  employed  as  the  assistant  in  dyeing  in  preference  to 
Glauber's  salt  or  common  salt. 

Silk  is  also  distinguished  by  its  great  strength.     It  is  said  that 
its  tensile  strength  is  almost  equal  to  that  of  an  iron  wire  of  equal 


82 


THE   TEXTILE  FIBRES. 


diameter.  The  silk  fibre  is  also  very  elastic,  stretching  15  to  20 
per  cent,  of  its  original  length  in  the  dry  state  before  breaking. 
Degummed  or  boiled-off  silk  is  much  lower  in  strength  and 
elasticity  than  raw  silk,  the  removal  of  the  silk-gum  apparently 
causing  a  decrease  of  30  per  cent,  in  the  tensile  strength  and 
45  per  cent,  in  the  elasticity.  The  weighting  of  silk  also  causes  a 
decrease  in  its  strength  and  elasticity. 

The  following  table  gives  the  diameter,  elasticity,  and  tensile 
strength  of  the  cocoon- thread  of  the  chief  varieties  of  silks  (Wardle, 
Jour.  Soc.  Arts,  xxxm.  671): 


Name  of  Silk. 

Coun- 
try. 

Diameter, 
Ins. 

Elasticity, 
Ins.  in  i  Ft. 

Tensile 
Strength, 
Drams. 

Size  of 
Cocoon, 
Ins. 

Outer 
Fibres. 

Inner 
Fibres. 

Outer 
Fibres. 

Inner 
Fibres. 

Outer 
Fibres. 

Inner 
Fibres. 

Bom  by  x  mori  
Bombvx  mori  

China 
Italy 
Japan 
Bengal 
India 
India 
India 
India 
India 
India 
India 
Japan 
India 
China 

.00052 
•00053 
.00057 
.00045 
.00042 
.00161 
.00085 
.00083 
.00128 

.00100 

.00102 

.00088 

.00118 

.00071 
.00068 
.00069 
.00051 
.00047 
.00172 
.00093 
.00097 
.00125 
.00109 
.001  I  I 
.00096 

.00120 
.00138 

•3 

.2 

.2 

.8 
•5 
•9 

2^6 

2.4 

2.0 
1-9 
2.0 

1.9 
1.9 
1.4 

2-3 
1.9 
2.7 

2.0 
2.9 
2.9 
2.8 
2.8 

4.0 

1.6 
1.9 

2.0 

1.6 
1.4 
6.6 

!-5 

2.4 

2.8 

2.4 

2.  I 

6.8 

2.6 
2.6 

3-1 

2.8 
2.6 

7.8 
3-° 
3-5 
4.8 
4.0 
4-.  i 
7-5 

.1X0.5 
.2X0.6 
.1X0.6 
.2X0.5 
.2X1.5 
.5X0.8 
.5X0.8 
.8X0.8 
.8X1.0 
3.0X1.2 
3.5X0.8 
1.5X0.8 
2.0X0.8 
1.6X0.8 

Bom  by  x  mori  
Bombvx  fortunatus 
Bombvx  textor  ..... 
Antheraea  mylitta.  .  . 
Attacus  ricini  
Attacus  cynthia.  .  .  . 
Antheraea  assama  .  . 
Actius  selene  
Attarus  atlas  
Antheraea  yama-mai. 
Cricula  trifenestrata 
Antheraea  pernyi.  .  .  . 

2.0 

2.7 

3-2 

5-8 

The  density  of  silk  in  the  raw  state  is  1.30  to  1.37,  while 
boiled-off  silk  has  a  density  of  1.25. 

Another  property  of  silk  which  is  peculiar  to  this  fibre,  ordi- 
narily, is  what  is  termed  its  scroop;  this  refers  to  the  crackling 
•;nd  emitted  when  the  fibre  is  squeezed  or  pressed.  To  this 
property  is  due  the  well-known  rustle  of  silken  fabrics.  The 
scroop  of  silk  does  not  appear  to  be  an  inherent  property  of  the 
fibre  itsc-lf,  but  is  acquired  when  the  silk  is  worked  in  a  bath  of 
dilute  acid  and  dried  without  washing.  A  satisfactory  explana- 
tion to  account  for  the  scroop  has  not  yet  been  given;  it  is 
probably  due  to  the  acid  hardening  the  surface  of  the  fibre. 


SILK:    ITS  ORIGIN  AND  CULTIVATION.  83 

Vercerized  cotton  can  also  be  given  a  similar  scroop  bv  such 
a  treatment  with  dilute  acetic  acid.  Wool,  under  certain  con- 
ditions of  treatment,  can  also  be  given  this  silk-like  scroop,  as, 
for  instance,  when  it  is  treated  with  chloride  of  lime  solutions 
or  with  strong  caustic  alkalies. 

4.  Silk-reeling. — The  silk  fibre  as  it  appears  in  trade  for  use 
in  the  manufacture  of  textiles  is  obtained  by  unreeling  the  cocoon. 
After  the  cocoons  have  been  spun  by  the  silkworms  they  are 
heated  in  an  oven  for  several  houn  at  a  temperature  of  60°  to  70°  C. 
for  the  purpose  of  killing  the  puoa  or  chrysalis  contained  within, 
before  the  latter  shall  have  developed  sufficiently  to  begin  cutting 
its  way  through  the  envelope  and  thus  destroy  the  continuity  of 
the  cocoon-thread.  Another  method  of  operation  is  to  steam  the 
cocoons;  this  requires  only  a  few  minutes  to  kill  the  pupa,  and 
is  said  to  be  preferable  to  the  oven-heating,  as  it  causes  less  damage 
to  the  fibre,  and  at  the  same  time  considerably  softens  the  silk- 
glue,  thus  rendering  the  subsequent  process  more  easy.  After 
the  killing  of  the  worms  is  accomplished  the  cocoons  are  sorted 
into  several  grades,  according  to  size,  color,  extent  of  damage, 
etc.,  after  which  they  are  ready  for  reeling.  This  is  entirely  a 
mechanical  process  requiring  much  skill.  The  cocoons  are 
soaked  in  warm  water  until  the  silk-glue  is  softened;  the  operator 
seizes  the  loose  ends  of  several  fibres  together  on  a  small  brush 
and  passes  them  through  the  porcelain  guides  of  a  reel,  where 
they  are  twisted  together  to  form  threads  of  sufficient  size  for 
weaving.  Two  threads  are  formed  simultaneously  on  each  reel, 
and  are  made  to  cross  and  rub  against  each  other  to  remove 
twists  in  the  fibre  (see  Fig.  296),  and  also  to  rub  the  softened 
silk-glue  coverings  together  in  order  that  the  fibres  may  become 
firmly  cemented  and  form  a  uniform  thread.  The  product  so 
obtained  is  termed  raw  silk  or  grege;  floss  silk,  which  is  used 
for  making  spun  silk,  is  the  term  applied  to  the  waste  result- 
ing from  short  and  tangled  fibres  from  the  exterior  of  the 
cocoon,  and  from  those  cocoons  which  have  been  broken  by 
the  moth  in  escaping.  Raw  silk  is  classified  into  two  grades: 
(a)  Organzine  silk,  which  is  made  from  the  best  selected  cocoons, 
and  is  chiefly  used  for  warps  on  account  of  its  greater  strength; 


84  THE   TEXTILE  FIBRES. 

and  (b)  Tram  silk,  which  is  made  from  the  poorer  quality  cocoons, 
and  is  mostly  employed  for  filling.  Floss  or  waste  silk  cannot 
be  reeled,  so  the  cocoon- threads  are  scoured  in  a  solution  of  soda 
and  soap,  and  afterwards  combed  and  carded  in  special  machines. 
The  better  quality  and  longer  fibre  is  worked  up  into  what  is 
known  as  ftorette  silk,  while  the  shorter  fibres  are  carded  and 
spun  into  bourette  silk.  Floss  silk  is  also  known  as  chappe  or 
ecliappe  silk. 


V 

I 


CHAPTER  VII. 
CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK. 

i.  Chemical  Constitution. — The  glands  of  the  silkworm  appear 
to  secrete  two  transparent  liquids.  The  one,  fibroin,  constituting 
from  one-half  to  two-thirds  of  the  entire  secretion,  forms  the  inte- 
rior and  larger  portion  of  the  silk  fibre;  the  other,  sericin,  also 
called  silk-glue,  forms  the  outer  coating  of  the  fibre.  The  latter 
substance  is  yellowish  in  color,  and  is  readily  soluble  in  boiling 
water,  hot  soap,  and  alkaline  solutions.  As  soon  as  discharged 
into  the  air  the  fluids  from  the  spinneret  solidify,  and  coming  into 
contact  with  each  other  at  the  moment  of  discharge,  are  firmly 
cemented  together  by  the  sericin. 

The  amount  of  sericin  present  in  raw  silk  is  about  25  per, 
cent.,  and  this  causes  the  fibre  to  feel  harsh  and  to  be  stiff  and 
coarse.  Before  being  manufuctured  into  textiles  the  raw  silk  is 
subjected  to  several  processes  with  a  view  to  making  it  soft  and 
glossy.  The  first  treatment  is  called  discharging,  stripping,  or 
ungumming,  and  has  for  its  purpose  the  removal  of  the  silk-glue. 
It  is  really  a  scouring  operation,  the  silk  being  worked  in  a  soap 
solution  *  at  a  temperature  of  95°  C.  In  this  process  the  silk 
loses  from  20  to  30  per  cent,  in  weight,  but  becomes  soft  and 
glossy.  After  several  successive  scourings  the  soap  solution 
becomes  heavily  charged  with  sericin,  and  is  subsequently  util- 
ized in  the  dye-bath  as  an  assistant  under  the  name  of  boiled-off 
liquor. 

*  Alkaline  carbonates  are  not  to  be  recommended  for  silk -scouring,  as  they 
are  liable  to  injure  the  fibre,  especially  at  elevated  temperatures.  Soft  water 
should  also  be  employed,  as  lime  makes  the  fibre  brittle. 

85 


86 


THE   TEXTILE  FIBRES. 


According  to  Mulder,  samples  of  yellow  Italian  silk  analyzed 
as  follows: 

Per  Cent. 

Silk  fibre 53-35 

Matter  soluble  in  water 28 . 86 

"alcohol 1.48 

"  ether o.oi 

"  "        "  acetic  acid 16. 30 

He  gives  the  chemical  composition  of  the  silk  fibre  as  follows: 

Per  Cent. 

Fibroin 53-37 

Gelatin 20.66 

Albumin 24 . 43 

Wax i .  39 

Coloring-matter o .  05 

Resinous  and  fatty  matter o.  10 

According  to  Richardson,   mulberry   silk  has  the  following 
composition : 

Per  Cent. 

Water 12 . 50 

Fats o.  14 

Resins 0.56 

Sericin 22 . 58 

Fibroin 63 . 10 

Mineral  matter 1.12 

Analysis  of  samples  of  mulberry  silk  is  given  by  H.  Silbermann 
as  follows: 


White. 


Cocoons.         Raw 


Yellow. 


Cocoons.          Raw 


Fibroin 

Ash  of  fibroin. 

Sericin 

Wax  and  fat.  , 
Salts 


73-59 
0.09 

22.  28, 
3.02 
I. 60 


76.  2O 
O.O9 

22. OI 
1.36 

0.30 


7O.02 

o.  16 

24.29 

3-46 

1.92 


72-35 
o.  16 


2-75 
i.  60 


The  amount  of  ash  in  boiled-off  silk  will  vary  somewhat 
according  to  the  origin  of  the  silk,  but  will  average  about  0.50 
per  cent.  In  raw  silk  the  average  amount  of  ash  will  be  about 
i  per  cent.  In  yama-mai  silk  the  ash  may  reach  as  high  as  8 
per  cent. 


CHEMICAL   NATURE  AND  PROPERTIES  OF  SILK.  87 

Fibroin  is  a  proteoid  somewhat  analogous  to  that  contained  in 
wool,  and,  like  the  latter,  it  is  no  doubt  an  amido-acid.*  Mulder 
gives  the  analysis  of  fibroin  as  follows: 

Per  Cent. 

Carbon 48 . 80 

Hydrogen 6. 23 

Oxygen 25 .  oo 

Nitrogen 19 .  oo 

Yignon  analyzed  samples  of  highly  purified  silk,f  and  gives 
the  following  figures: 

Per  Cent. 

Carbon 48 . 3 

Hydrogen 6.5 

Nitrogen ' 19.2 

Oxygen 26.0 

The  proportion  of  fibroin  in  raw  silk  has  been  variously 
stated  by  different  observers,  and  appears  to  differ  with  the 
method  employed  for  its  determination.  The  figure  given  by 
Mulder  (see  above)  of  53.35  per  cent,  was  obtained  by  boiling 
the  raw  silk  with  acetic  acid.  By  the  action  of  a  5  per  cent, 
solution  of  cold  caustic  soda,  Stadeler  obtained  42  to  50  per  cent, 
of  fibroin.  Cramer  obtained  66  per  cent,  by  heating  raw  silk 
in  water  at  i33°C.  under  pressure.  Francezon  reports  75  per 
cent,  of  fibroin  by  twice  boiling  the  silk  in  a  solution  of  soap  and 
then  treating  with  acetic  acid.  Vignon,  by  carefully  purifying 
the  fibroin  by  suitable  treatment,  obtained  75  per  cent. 

*  Richardson  suggests  the  following  structural  formula  for  fibroin,  allowing  x 
to  represent  a  hydrocarbon  residue: 

xNH— CO^ 

X(  )X. 

\CO— NH/ 

The  decomposition  of  fibroin  by  saponification  with  potash  would  then  be 
/NH— OX  ^NH2 

\co— NH/  \:O.OK* 

f  Vignon  prepared  pure  fibroin  in  the  following  manner:  A  lo-gram  skein 
of  raw  white  silk  is  boiled  for  thirty  minutes  in  a  solution  of  15  grams  of  neutral 
soap  in  1500  c.c.  water;  rinse  in  hot,  then  in  tepid  water;  squeeze  and  repeat  the 
treatment  in  a  fresh  soap-bath;  rinse  with  water,  then  with  dilute  hydrochloric 
acid,  again  with  water;  finally,,  wash  twice  with  90  per  cent,  alcohol.  The  fibroin 
thus  obtained  leaves  only  o.oi  per  cent,  of  ash  on  ignition.  (Compt.  rend.,  cxv. 
17,  613). 


88  THE   TEXTILE  FIBRES. 

Unlike  keratin,  the  proteoid  of  wool,  fibroin  contains  no  sul- 
phur, and  is  much  more  constant  in  its  composition.  The  empiri- 
cal formula  for  fibroin  as  given  by  Mulder  is  C15N23N5O6.  Mills 
and  Takamine  give  the  formula  as  C24H38N8Od,  while  Schiitzen- 
berger  gives  C71H107N24O25.  Cramer  arrives  at  the  same  formula 
as  Mulder,  while  Richardson  (Jour.  Soc.  Chem.  Ind.,  xn.  426) 
gives  C^Hj^NjgOzs-  Vignon's  formula  for  specially  purified 
fibroin  is  C22H47N10O12-* 

The  presence  of  the  amido-group  in  fibroin  has  been  shown, 
as  in  the  case  of  wool  (see  page  37),  by  diazotizing  the  fibre 
with  an  acid  solution  of  sodium  nitrite,  then  washing  and  treating 
with  solutions  of  various  developers,  such  as  phenol,  resorcinol, 
alpha-  and  beta-naphthols,  etc.,  whereby  the  fibre  becomes  dyed 
in  different  colors. 

From  its  action  towards  alcoholic  potash  Richardson  con- 
cludes that  silk-fibroin  is  more  probably  an  amido- anhydride 
rather  than  an  amido-acid.  When  boiled  for  a  long  period  with 
dilute  sulphuric  acid  fibroin  is  dissolved  to  a  yellowish  brown 
liquid,  leaving  as  a  residue  only  a  small  amount  of  what  is  appar- 
ently a  fatty  acid.  From  this  decomposition  product  Weyl 
(Ber.,  xxi.  1529)  succeeded  in  isolating  5.2  per  cent,  of  tyrosin, 
7.5  per  cent,  of  glycocin,  and  15  per  cent,  of  a  crystalline  com- 
pound which  was  apparently  alpha-alanin.  Towards  Millon's  and 
Adamkiewitz's  reagents  fibroin  gives  the  usual  reaction  of  pro- 
teids,  and  it  also  gives  the  biuret  test.f  According  to  Richardson, 

*  Silbermann  found  that  fibroin  heated  with  a  solution  of  barium  hydrate 
under  pressure  was  decomposed  with  the  formation  of  oxalic,  carbonic,  and  acetic 
acids,  together  with  an  amido  body  approximating  the  formula  C^H^N^O^. 
The  latter  compound  is  said  to  undergo  further  decomposition  with  the  formation 
of  tyrosin,  glycocin,  alanin,  amido-butyric  acid,  and  an  amido-acid  of  the  acrylic 
series. 

t  Millon's  reagent  consists  of  a  solution  of  mercurous  nitrate  containing  nitrous 
acid  in  solution.  It  is  prepared  by  treating  i  c.c.  of  mercury  with  10  c.c.  of  nitric 
acid  (sp.  gr.  1.4),  heating  gently  until  complete  solution  is  effected,  then  diluting 
the  solution  with  twice  its  volume  of  cold  water.  When  a  solution  of  a  protiid 
i-  treated  with  this  reagent  a  white  precipitate  is  first  formed  which  turns  brick- 
red  on  lx)iling;  a  solid  proteid  becomes  red  when  boiled  with  the  reagent.  Adam- 
kirwitx's  test  is  to  dissolve  the  proteid  in  glacial  acetic  acid,  and  then  add  con- 
centrated sulphuric  acid  to  the  solution,  when  a  fine  violet  color  will  be  produced, 
and  the  liquid  will  exhibit  a  faint  fluorescence.  The  biuret  test  is  to  add  a  few 


CHEMICAL   NATURE  AND  PROPERTIES   OF  SILK.  89 

silk-fibroin  will  absorb  30  per  cent,  of  iodin  when  treated  with 
Hiibl's  reagent.  Attempts  have  been  made  to  acetylize  fibroin, 
but  without  success. 

Fibroin  Is  insoluble  in  ammonia  and  solutions  of  the  alka- 
line carbonates;  neither  is  it  dissolved  by  a  i  per  cent,  solution 
of  caustic  soda,  but  stronger  solutions  affect  it,  especially  if  hot. 
From  its  solution  in  caustic  soda  fibroin  may  be  reprecipitated 
by  dilution  with  water.  Fibroin  is  also  soluble  in  hot  glacial 
acetic  acid,  and  in  strong  hydrochloric,  sulphuric,  nitric,  and 
phosphoric  acids.  Alkaline  solutions  of  the  hydroxides  of  such 
metals  as  nickel,  zinc,  and  copper  also  dissolve  fibroin. 

If  silk-fibroin  is  dissolved  in  cold  concentrated  hydrochloric 
acid,  and  the  solution  be  allowed  to  stand  sixteen  hours  at  the 
ordinary  temperature  with  three  times  its  volume. of  hydro- 
chloric acid  (sp.  gr.  1.19),  it  will  no  longer  be  precipitated  by  the 
addition  of  alcohol.  The  fibroin  appears  to  have  suffered  hy- 
drolysis, being  converted  into  a  body  similar  to  peptone.  This  sub- 
stance may  be  separated  out  by  steaming  the  above  solution  under 
diminished  pressure.  If  its  aqueous  solution  be  neutralized 
with  ammonia  and  some  trypsin  ferment  be  added,  tyrosin  will 
begin  to  crystallize  out  in  a  few  hours. 

Sericin,  according  to  the  analysis  of  Richardson,  has  the 
following  composition : 

Per  Cent. 

Carbon 48 . 80 

Hydrogen 6.23 

Oxygen 25.97 

Nitrogen I9.oo 

and  its  formula  is  given  as  C16H25N5O8.  It  is  considered  as 
probably  being  an  alteration  of  fibroin;  strong  hydrochloric  acid 
is  said  to  convert  the  latter  into  sericin;  the  conversion  is  supposed 
to  take  place  by  assimilation  of  water  and  oxygen: 

C15H23N506+  H20+  O  =C1<ft,N808. 

Fibroin  Sericin 


drops  of  a  dilute  solution  of  copper  sulphate  to  the  solution  of  proteid;  on  then 
adding  an  excess  of  caustic  soda  solution  the  precipitate  which  at  first  formed  will 
be  dissolved  with  the  production  of  a  fine  violet  coloration. 


90  THE   TEXTILE  FIBRES. 

Sericin  may  be  obtained  in  a  pure  condition  by  first  boiling  a 
sample  of  raw  silk  in  water  for  several  hours*  after  which  the 
sericin  is  precipitated  by  lead  acetate.*  On  treatment  with 
dilute  sulphuric  acid  sericin  yields  a  small  quantity  of  leucin 
and  tyrosin,  but  no  trace  of  glycocoll,  the  principal  product 
formed  being  a  crystalline  body  called  serin,  which  appears  to 
have  the  formula  C3H7NO3,  and  from  its  chemical  reactions  is 
evidently  analogous  to  glycocin,  probably  being  amido-glyceric 
acid. 

Sericin  is  soluble  in  hot  water,  hot  soap  solutions,  and  dilute 
caustic  alkalies.  The  aqueous  solution  is  precipitated  by  alcohol, 
tannin,  basic  lead  acetate,  stannous  chloride,  bromine,  and 
iodine,  and  by  potassium  ferrocyanide  in  the  presence  of  acetic 
acid.f  Mulder  gives  the  formula  of  C15H25N5O8  to  sericin,  and 
the  following  composition: 

Per  Cent. 

Carbon 42.60 

Hydrogen 5 . 90 

Oxygen. 35 .  oo 

Nitrogen 16. 50 

According  to  Bolley,  the  composition  of  sericin  is: 

Per  Cent. 

Carbon 44-32 

Hydrogen 6.18 

Oxygen 31-20 

Nitrogen 18. 30 

*  Pure  sericin  may  also  be  prepared  by  precipitating  crude  sericin  solution 
with  i  per  cent,  acetic  acid,  washing  the  separated  sericin  by  repeated  decantn- 
tion  with  water,  then  treating  with  cold  and  afterwards  with  boiling  alcohol, 
and  finally  extracting  with  ether.  Pure  sericin  contains: 

C 45-oo  per  cent. 

H 6.32    "      " 

N 17.14    "      " 

0 31.54    "      " 

It  is  easily  soluble  in  water,  in  concentrated  hydrochloric  acid,  and  in  potas- 
sium carbonate;  sodium  carbonate  only  causes  a  swelling. 

f  By  treatment  with  formaldehyde  it  is  claimed  that  sericin  is  rendered  in- 
soluble in  Ixrth  hot  water  and  soap  solutions;  consequently  raw  silk  may  be 
treated  with  this  reagent  for  use  in  certain  applications  where  it  may  be  desired 
to  retain  as  far  as  possible  the  coating  of  silk-glue. 


CHEMICAL  NATURE  AND  PROPERTIES   OF  SILK.  91 

Yignon,*  by  observing  the  action  of  solutions  of  sericin  and 
fibroin  on  polarized  light,  found  that  both  of  these  constituents 
of  silk  were  laevogyrate,  and  their  rotatory  powers  were  about 
equal,  approximating  to  40°.  This  is  in  keeping  with  observa- 
tions made  on  other  albuminoids. 

According  to  Dubois,f  the  yellow  coloring-matter  of  silk  is 
similar  to  carotin.  He  obtained  five  different  bodies  from  the 
natural  coloring-matter  of  silk,  as  follows:  (i)  a  golden-yellow 
coloring-matter,  soluble  in  potassium  carbonate  and  precipitated 
by  acetic  acid;  (2)  crystals  which  appear  yellowish  red  by  trans- 
mitted light  and  brown  by  reflected  light;  (3)  a  lemon-colored 
amorphous  body,  the  alcoholic  solution  of  which  on  evaporation 
gave  granular  masses;  (4)  yellow  octahedral  crystals  resembling 
sulphur;  (5)  a  dark  bluish  green  pigment  in  minute  quantities 
and  probably  crystalline. 

2.  Chemical  Reactions. — In  its  general  chemical  behavior 
silk  i^  quite  similar  to  wool.  It  will  stand  a  higher  temperature, 
however,  than  the  latter  fibre,  without  receiving  injury;  it  can 
be  heated,  for  instance,  to  110°  C.  without  danger  of  decomposi- 
tion; at  170°  C.,  however,  it  is  rapidly  disintegrated.  On  burning 
it  liberates  an  empyreumatic  odor  which  is  not  as  disagreeable 
as  that  obtained  from  burning  wool.  Silk  readily  absorbs  dilute 
acids  from  solutions,  and  in  so  doing  increases  in  lustre  and 
acquires  the  scroop  of  which  mention  has  already  been  made. 
Unlike  wool,  it  has  a  strong  affinity  for  tannic  acid,  which  fact 
is  utilized  for  both  weighting  and  mordanting  the  fibre.  Silk 
also  absorbs  sugar  to  a  considerable  degree,  and  this  substance 
may  be  employed  as  a  weighting  material  for  light-colored  silks 
on  th  s  account.  Towards  the  ordinary  metallic  salts  used  as 
mordants  silk  exhibits  quite  an  affinity;  in  fact,  to  such  an  extent 
can  it  absorb  and  fix  certain  metallic  salts  that  silk  material  is  I 
frequently  heavily  mordanted  with  such  salts  for  the  purpose  \ 
of  unscrupulously  increasing  its  weight. 

Solutions  of  sodium  chloride  appear  to  have  a  peculiar  action 
on  the  silk- fibre,  especially  in  the  presence  of  weighting  materials. 

*  Compt.  rend.,  CXHI.  802.  t  Ibid.^  cxi.  482. 


92  THE   TEXTILE  FIBRES. 

According  to  the  researches  of  Sisley,  solutions  of  common  salt 
acting  on  weighted  silk  in  the  presence  of  air  and  moisture  cause 
a  complete  destruction  of  the  fibre  in  twelve  months  if  charged 
with  but  0.5  per  cent,  of  salt;  i  per  cent,  of  salt  causes  a  very 
pronounced  tendering  of  the  fibre  in  two  months,  while  2  to  5  per 
cent,  of  salt  causes  a  distinct  tendering  in  seven  days.  The  action 
of  the  salt  is  shared  in  a  lesser  degree  by  the  chlorides  of  potassium, 
ammonium,  magnesium,  calcium,  barium,  aluminium,  and  zinc, 
and  is  probably  due  to  chemical  dissociation.  This  fact  may 
account  for  the  stains  sometimes  found  in  skeins  of  silk  which 
also  show  a  tendering  of  the  fibre.  These  stains  have  frequently 
been  noticed,  and  thorough  investigation  has  failed  to  satisfactorily 
account  for  them.  The  salt  may  get  into  the  fibre  through  the 
perspiration  of  the  workmen  handling  the  goods,  or  through  a 
variety  of  other  causes. 

Silk  is  not  as  sensitive  to  dilute  alkalies  as  wool,  though  the 
lustre  of  the  fibre  is  somewhat  diminished.*  When  treated  with 
strong  hot  alkalies  the  silk  fibre  dissolves.  Ammonia  and  soaps' 
have  no  effect  on  silk  beyond  dissolving  off  the  silk-glue  or  seri- 
cin;  though  on  long-continued  boiling  in  soap,  the  fibroin  is  also 
attacked.  Concentrated  sulphuric  f  and  hydrochloric  acids  dis- 
solve silk;  nitric  acid  colors  silk  yellow,  J  as  in  the  case  with  wool, 

*  It  is  said  that  when  mixed  with  glucose  or  glycerin  caustic  soda  does  not 
dissolve  the  silk  fibre  to  any  extent,  but  only  removes  the  gum. 

f  Though  silk  is  soluble  in  concentrated  acids  if  their  action  is  continued 
for  any  length  of  time,  it  appears  that  if  silk  be  treated  with  concentrated  sul- 
phuric acid  for  only  a  few  minutes,  then  rinsed  and  neutralized,  the  fibre  will 
contract  from  30  to  50  per  cent,  in  length  without  otherwise  suffering  serious 
injury  beyond  a  considerable  loss  in  lustre.  This  action  of  concentrated  acids  on 
silk  has  been  utilized  for  the  creping  of  silk  fabrics,  the  acid  being  allowed  to  act 
only  on  certain  parts  of  the  material.  It  appears  that  tussah  silk  is  not  affected 
by  the  acid  to  the  same  degree  as  ordinary  silk,  and  hence  creping  may  be 
accomplished  by  mixing  tussah  with  ordinary  silk,  and  treating  the  entire  fabric 
with  concentrated  acid. 

J  The  action  of  nitric  acid  on  silk  is  rather  a  peculiar  one.  When  treated 
for  one  minute  with  nitric  acid  of  sp.  gr.  1.33  at  a  temperature  of  45°  C.,  the  silk 
acquires  a  yellow  color  which  cannot  be  washed  out  and  is  also  fast  to  light.  Pure 
nitric  acid  free  from  nitrous  compounds,  however,  does  not  give  this  color.  On 
treating  the  yellow  nitro -silk  with  an  alkali  the  color  is  ( onsiderably  deepened. 
With  strong  sulphuric  acid  nitro-silk  swells  up  and  gives  a  gelatinous  mass  re- 
sembling egg  albumin. 


CHEMICAL   NATURE  AND  PROPERTIES  OF  SILK.  93 

probably  due  to  the  formation  of  xanthroproteic  acid.  This 
color  can  be  removed  by  treatment  with  a  boiling  solution  of 
stannous  chloride.  A  concentrated  solution  of  basic  zinc  chlo- 
ride readily  dissolves  the  silk  fibre.*  An  acid  solution  of  zinc 
chloride  also  acts  in  the  same  manner.  Solutions  of  copper 
oxide  or  nickel  oxide  in  ammonia  also  act  as  solvents  towards 
silk.  The  latter  solution  can  be  employed  for  separating  silk 
from  cotton,  the  silk  being  readily  and  completely  soluble  in  a 
boiling  solution  of  ammoniacal  nickel  oxide,  whereas  cotton  loses 
less  than  i  per  cent,  of  its  weight.  A  boiling  solution  of  basic 
zinc  chloride  (i :  i)  will  dissolve  silk  in  one  minute,  while  cotton 
under  the  same  treatment  loses  only  0.5  per  cent.,  and  wool  only 
1.5  to  2  per  cent.f  Chlorine  destroys  silk,  as  do  other  oxidizing 
agents,  unless  employed  in  very  dilute  solutions  and  with  great 
care. 

Hydrofluosilicic  acid  and  hydrofluoric  acid  in  the  cold  and  in 
5  per  cent,  solutions  do  not  appear  to  exert  any  injurious  action 
on  the  silk- fibre;  these  acids,  however,  remove  all  inorganic 
weighting  materials,  and  their  use  has  been  suggested  for  the 
restoring  of  excessively  weighted  silks  to  their  normal  condition, 
so  that  they  may  be  less  harsh  and  brittle. 

Towards  coloring-matters  in  general,  silk  exhibits  a  greater 
capacity  of  absorption  than  perhaps  any  other  fibre.  It  also 
absorbs  dyestuffs  at  much  lower  temperatures  than  does  wool. 

3.  Tussah  Si'k  presents  a  number  of  differences,  both  physi- 
cally and  chemically,  from  ordinary  silk.  It  has  a  brown  color 
and  is  considerably  stiffer  and  coarser.  It  is  less  reactive,  in 
general,  towards  chemical  reagents,  and  consequently  presents 


*  On  diluting  this  solution  with  water  a  flocculent  precipitate  is  obtained 
which  is  soluble  in  ammonia,  and  the  latter  solution  has  been  employed  for  coat- 
ing vegetable  fibres  with  silk  for  the  production  of  certain  so-called  "artificial 
silks." 

f  Silk  is  also  soluble  in  Schweitzer's  reagent  (cupro-ammonium  hydrate),  and 
in  an  alkaline  solution  of  copper  sulphate  and  glycerin.  The  latter  is  used  to 
separate  silk  from  wool  and  cotton;  and  the  following  solution  is  recommended: 
1 6  grams  copper  sulphate,  10  grams  glycerin,  and  150  c.c.  of  water.  After  dis- 
solving, add  a  solution  of  caustic  soda,  until  the  precipitate  which  at  first  forms 
is  just  redissolved. 


94  THE   TEXTILE  FIBRES. 

more  difficulty  in  bleaching  and  dyeing.  Tussah  silk  requires 
a  much  more  severe  treatment  for  ungumming  than  cultivated 
silk,  and  the  boiled-off  liquor  so  obtained  is  of  no  value  in  dyeing. 
According  to  analyses  of  Bastow  and  Appleyard  *  raw  tus- 
sah  silk  gives  the  following  results: 

Per  Cent 

Soluble  in  hot  water 21 . 33 

Dissolved  by  alcohol  (fatty  acid) 0.91 

Dissolved  by  ether o .  08 

Total  loss  on  boiling  off  with  i  per  cent,  solution 

of  soap 26 . 49 

Mineral  matter 5 . 34 

These  same  observers  consider  that  the  fibroin  of  tussah  silk 
differs  chemically  from  that  of  ordinary  silk,  as  it  is  much  less 
readily  acted  on  by  solvents.  In  order  to  obtain  pure  tussah 
fibroin  the  silk  should  be  boiled  repeatedly  with  a  i  per  cent. 
solution  of  soap,  washed  with  water,  extracted  with  hydrochloric 
acid;  and  after  again  washing  with  water  and  drying,  extracted 
successively  with  alcohol  and  ether.  Tussah  fibroin  purified  in 
this  manner  shows  the  following  composition: 

Per  Cent. 

Carbon 47 . 18 

Hydrogen 6 . 30 

Nitrogen 16.85 

Oxygen 29 . 67 

These  figures  are  exclusive  of  0.226  per  cent,  of  ash.  Apple- 
yard  gives  the  following  analysis  of  the  ash  from  raw  tussah 
silk: 

Per  Cent. 

Soda,  Na2O 12 . 45 

Potash,  K2O 31 . 68 

Alumina,  A12O3 i .  46 

Lime,  CaO J3-32 

Magnesia,  MgO 2.56 

Phosphoric  acid,  P2O6 6.90 

Carbonic  acid,  CO2 11.14 

Silica,  SiO2 9.  79 

Hydrochloric  acid,  Cl 2 . 89 

Sulphuric  acid,  SO3 8. 16 

*  Jour.  Soc.  Dyers'  and  Col.,  rv.  88. 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK. 


95 


The  presence  of  sulphates  in  this  ash  is  somewhat  remark- 
able, as  this  constituent  does  not  occur  in  ordinary  silk.  The 
occurrence  of  alumina  is  also  remarkable,  as  this  element  is  sel- 
dom a  constituent  of  animal  tissues.  As  the  amount  of  ash  of 
purified  fibroin  of  both  common  silk  and  tussah  silk  is  very 
much  lower  than  that  of  the  raw  silks,  it  is  ta  be  considered  prob- 
able that  most  of  the  mineral  matter  found  is  derived  from  adher- 
ing impurities,  and  is  not  a  true  constituent  of  the  silk  itself. 

Tussah  silk  is  scarcely  affected  by  an  alkaline  solution  of 
copper  hydrate  in  glycerin,  whereas  ordinary  silk  is  readily 
soluble  in  this  reagent.* 

The  following  table  exhibits  the  principal  differences  between 
true  silk  and  tussah  silk:| 


Reagent. 

True  Silk. 

Tussah  Silk. 

Hot  caustic  soda  (10%) 

Cold    hydrochloric    acid    (sp. 
gr.  1.16) 
Cold  cone,  nitric  acid 
Neutral  solution  of  zinc  chlo- 
ride (sp.  gr.  1.725) 
Strong  chromic  acid  solution 
in  water 

Dissolves  in  12  minutes 
Dissolves  very  rapidly 

Dissolves  in  5  minutes 
Dissolves  very  rapidly 

Dissolves  very  rapidly 

Requires  50  minutes  for 
solution 
Only  partially  dissolves 
in  48  hours 
Dissolves  in  10  minutes 
Dissolves  but  slowly 

Dissolves  very  slowly 

While  the  fibre  of  true  silk  presents  the  appearance  of  a 
structureless  thread,  and  rarely  exhibits  signs  of  distinct  striation, 
tussah  (and  other  "wild"  silks)  is  made  up  of  bundles  of  delicate 
fibrillae,  varying  in  diameter  from  0.0003  to  0.0015  mm.,  so  that 
the  fibre  as  a  whole  presents  a  striated  appearance.  Also  the 
cross-section  {  of  tussah  silk  is  considerably  larger  than  that 
of  true  silk,  and  is  more  flattened;  it  also  exhibits  numerous 
fine  air-tubes.  The  following  table  exhibits  the  difference  in 
the  microscopic  appearance  of  various  kinds  of  raw  silk;  the 
diameter  is  expressed  in  fj.  =  thousandths  of  a  millimeter  :§ 


*  Filsinger,  Chem.  Zeit.,  xx.  324. 

t  Bastow  and  Appleyard,  Jour.  Soc.  Dyers'  and  Co/.,  rv.  89. 

J  Filsinger,  vide  supra. 

§  Hohnel,  Jour.  Soc.  Chem.  Ind.,  n.  172. 


96 


THE   TEXTILE  FIBRES. 


Variety  of  Silk. 

Diameter. 

Appearance. 

Broad  Side.                              Narrow  Side. 

True  silk,  Bombyx 

20  to  25 

White      or      yellowish; 

White      or      vellowish; 

mori 

shiny 

Shinv    ' 

Senegal     silk,     B. 
jaidherbi 

30  to  35 

Shining     yellowish     or    Gray,  brown,  or  black, 
brownish     white,    or        with        occasionally 

pale     yellow,      gray,         lighter  shades 

brown,  and  occasion- 

ally bluish  white 

Ailanthus  silk,  B. 

40  to  50 

Shining  yellowish  white,    Dirty  gray  or  brown  to 

cynthia 

with  yellow,  brown,  or        black,  with  green,  yel- 

brownish-gray  spots           low,  red,  violet,  or  blue 

spots 

Yama-mai     silk, 

40  to  50 

Bluish  white  with  dark    Glaring  and  fine  colors, 

Anther  aa  yama- 

blue,  blue  and  black        with    dark    or    black 

mai 

shaded                                  shades 

Tussah  silk,  Actius 

50  to  55 

Irregular   in   thickness.     Dark  gray,  with  pink  or 

selene 

Thickest    parts    with 

light  green  spots 

gray  and  blue  spots; 

thinner   parts    bluish 

white,       yellow,      or 

orange-red 

Tussah    silk,    An- 

60  to  65 

Similar    to   above,    but  j  Similar  to  above 

theraa  mylitta 

spots  orange-red,  red, 

or  brown 

CHAPTER 

THE  VEGETABLE  FIBRES. 

i .  THE  basis  of  all  vegetable  fibres  is  to  be  found  in  cellulose, 
a  compound  belonging  to  a  class  of  naturally  occurring  sub- 
stances known  as  carbohydrates.  The  fibres  may  be  either 
seed-hairs,  such  as  the  different  varieties  of  cotton,  cotton-silk, 
etc.;  or  bast  fibres,  which  include  those  obtained  from  the  cam- 
bium layer  of  the  dicotyledonous  plants,  such  as  flax,  hemp, 
jute,  ramie,  etc. ;  or  vascular  fibres,  which  include  those  obtained 
chiefly  from  the  leaf-tissues  of  the  monocotyledonous  plants, 
such  as  phormium,  agave,  aloe,  etc.* 

Anatomically  considered,  the  plant  fibres  may  be  divided  into 
six  different  classes  (Hohnel): 

(1)  Single-cell  plant-hairs,  such  as  cotton,  vegetable  silk,  and 
vegetable  down. 

(2)  Fibres   consisting  of   several   cells,   such   as   pulu   fibre, 
elephant- grass,  and  cotton-grass. 

(3)  Bast  fibres,  such  as  flax,  hemp,  jute,  ramie,  etc. 

(4)  Dicotyledonous   bast  fibres,  such    as  linden-bast,   Cuba 
bast,  etc. 

(5)  Monocotyledonous  vascular  fibres,   such  as   sisal   hemp, 
aloe-hemp,  pineapple  fibre,  cocoanut  fibre,  etc. 


*  There  is  a  peculiar  instance  in  which  the  entire  plant  is  used  as  the  fibre; 
this  is  sea-grass  or  sea -wrack  (Zostera  marina).  However,  it  can  scarcely  be 
considered  as  a  textile  fibre,  as  it  is  almost  altogether  employed  for  stuffing  and 
packing. 

97 


98  THE    TEXTILE  FIBRES. 

(6)  Monocotyledonous      schlerenchymous     fibres,     such     as 
Manila  hemp,  New  Zealand  flax,  etc. 

There  is  considerable  difference  to  be  observed  between  the 
anatomical  structure  of  seed- hairs  and  that  of  bast  fibres.     Seed- 
hairs  are  known  botanically  as  plumose  fibres,  and  consist  of  a 
unicellular  fibre  or  trichrome,  exhibiting  only  a  single  solid  apex, 
the   other   end    being   attached    to   the   seed.      Externally    they 
appear  to  be  covered  with  a  thin   skin  or  cuticle  which  differs 
essentially  from  the  remaining  cellulose  in  that  it  is  not  dissolved 
by   treatment   with    sulphuric   acid.      The   cell-walls   vary   con- 
siderably in  their   thickness,  and  are  structureless  and  porous. 
Through  the  centre  of  the  fibre  runs  a  hollow  canal,  called  the 
lumen,  the  chief  content   of  which  appears  to  be  air.     Usually 
the  dried  fibre  is  flattened  into  the  form  of  a  band,  and  the  lumen 
then  becomes  almost  nothing.     Bast  fibres,  on  the  other  hand, 
consist  of  completely  enclosed   tubes,   each  end   being  pointed. 
Each  individual  fibre  is  multicellular,  the  cells  being  long  and 
usually  polygonal  in  cross- section.      The  cell-walls    are  usually 
rather  thick,  and  the  cross- section  instead  of  being  flat  and  narrow 
is  broad  and  more  or  less  rounded.     The  inner  wall  is  frequently 
covered  with  a  thin  layer  of  dried  protoplasm.      One  of  the  most 
characteristic  appearances  of  the  bast  fibres  is  the  occurrence 
of  dislocations  or  joints  throughout  the  length  of  the  fibre.     These 
dislocations   also  show  the  property  of   becoming    more    deeply 
colored  than  the  rest  of  the  fibre  when  treated  with  a   solution 
of  chlor-iodide  of  zinc.      These  knots  of  joints  generally  show 
thicker   overlying   transverse  fissures,  between    which  lie    small 
short  discs  arranged  on  edge.     The  joints  disappear  altogether 
in  the  monocotyledonous  fibres;   they  are  also  lacking  on  many 
true  bast  fibres,  such  as  jute,  linden-bast,  etc.,  but  occur  in  hemp, 
flax,  ramie,  etc. 

Bast  fibres  are  the  long,  tough  cells  found  in  the  bark  and 
stem  of  various  plants.     The  cell- walls  of  these  fibres  are  usually 
partially  changed  from  pure  cellulose  into  lignin  and  are  thickened. 
There  is  usually  a  considerable  amount  of  foreign  matter  also  . 
contained  in  the  cell-wall,  and  often  this  becomes  sufficiently 
characteristic   to  serve  as  a  means  of  identifying  the   various 


THE   VEGETABLE  FIBRES. 


99 


fibres  by  the  application  of  chemical  reagents.  Unlike  seed- 
hairs,  the  individual  cells  of  bast  fibres  are  not  of  sufficient  length 
for  use  in  spinning,  but  as  they  are  held  together  with  considerable 
firmness  to  form  bundles  of  great  length,  they  are  utilized  in  this 
form. 

Wiesner  gives  the  following  table  showing  the  length  of  the 
raw  fibre  and  the  dimensions  of  the  cells  composing  them: 


Fibre 

Length  of 
Raw  Fibre, 
cm 

Length  of 
Cells, 
mm. 

Breadth  of  Cells. 

Min.  ,«. 

Max.  ft. 

Aver,  ft 

Tillandsia  fibre 

2—22 

O    2—       - 

6 

IO—4O 

I     ^—  I    O 

T  - 

(fordid  Idtijolid 

TO-QO 

o  i—  i  6 

M7 

16  8 

Phormium  tendx 

80—  no 

2     ?—  ?    6 

8 

2Q 

\bcltnochus  tetrdphyllos..       ... 

60—70 

o  i—  i  6 

8 

2O 

Bcinhinid  racemoso  

I  .  s—  4    O 

8 

2O 

Jute  (Corchorus  Cdpsularis}  
Thcspesid  Idtnpds 

150-300 
100—180 

0.8-4.1 
O    Q—  4.    7 

10 

21 

Urcnd  sinudtd 

IOO—  I2O 

Sidd  retusd 

8o—IOO 

0    8-2    3 

i  - 

2  ^ 

Cdlotropis  gigdntfd  (bast)  

2O—JO 

o  7—3  o 

18 

o  - 

Aloe  perjolidtd.            

I    3—37 

i  - 

24. 

Flax  (Linittn  usitdtissimuni) 

Hemp  (Cdnndbis  scitivd) 

IOO—3OO 

o  8—4  i 

16 

Jute  (Corchorus  olitorius)  

0.8-4  i 

16 

32 

Hibiscus  ccinndbinus 

4O—  OO 

4  o—  12  o 

20 

41 

Sunn  (Crotoldrid  junced) 

O    5—6    Q 

20 

42 

Bromelid  kdrdtds 

IOO—  I  IO 

I    4—6   7 

27 

42 

China  crass  (Bohmerid  niveo.)      .  . 

22    O 

40 

80 

Ramie  (Bohmerid  tendcissimd)  

8  o 

16 

12    6 

Cotton  (Gossypium  bdrbddcnse) 

_ 

IO    2 

do      (G   conalomerdtutn),  . 

3-  T 

•2S      I 

17 

27     I 

do      (G.  lierbdceuiri)  

1.82 

18.2 

II  .0 

^/  .  j. 
22 

do      (G   dcumindtuni) 

2    84 

28    4 

2O    I 

2O    0 

do      (G   drboreum) 

2    50 

2r    o 

2O 

37    8 

Cotton  wool  (Bombdx  heptdphyllum)  . 
Vegetable  silk  (Cdlotropis  gigdnted).  . 
do             (Asclepids)  

2-3 
2-3 

20-30 
20-30 
IO—3O 

19 
12 
2O 

29 
42 
44 

do.            (^larsdcnid)  

IO—  2? 

10 

33 

do.            (Strophdnthus)  

io—  ?6 

40 

02 

33 

Linden-bast 

1     1—2    6 

5 

Sterculid  villosd 

\---7      - 

17 

2- 

Holoptclid  intcgrifolid      .  . 

O    Q—  2     I 

14 

Kydtd  cdlycind                

1—2 

17 

24 

Ldsoisyphon  speciosus  

0.4—  c  .  i 

8 

20 

Sponid  ivightii           «  

4 

Pita  fibre  

I  .  O—  2  .  2 

16 

21 

o  4—0  o 

12 

2O 

II 


1 6 

io 


5° 

25.2 

25-5 
18.9 
29.4 
29.9 

38 


100 


THE   TEXTILE  FIBRES. 


Yetillard  gives  a  somewhat  similar  table  as  follows: 


Name. 

Length  (in  mm.).  |      Breadth  (in  //). 

i 

Ratio  of 
Breadth  to 
Length. 

Min. 

Max. 

Mean.    Min. 

Max. 

Mean. 

Linen   

4 

5 

4 
4 
60 

66 

55 
i9 
57 
250 

25 

12 

9 
16 
18 
40 
6 
5 

6 

3 
3--S 
4-5 
9 

10 
2-5 

'1 

6 
4 

12 

25 
20 
10 

27 
120 
10 

8 
5 

10 
10 

5 

2 
2 

5 

2 

i-5 

2-5 

5 

5 

2 

9 
4 

3 

6'5 

5 
3 
3 

2-5 

2-5 

a 

s 

12 
20 

25 
10 

37 
5° 
26 
70 
80 

50 
25 

20 
22 

16 

50 
5° 
3° 
30 

15 
20 

3° 
21 

16 

22.5 

22 
12 

15 
6 

24 
13 

16 

15 

20 

24 
24 
28 

20 

24 
II 

16 

12 

20 

1200 
1000 

620 

55° 
2400 

35° 
260 

330 

500 

330 

240 

125 
90 
500 
QO 
125 
160 
830 

210 

J5° 
55° 
170 

!50 
IOO 

250 

180 
150 

120 
2^0 

160 

130 

35 

Hemp  (Cannabis  saliva}  

Hop  fibre  (Humulus  lit  put  us) 

^settle  fibre  (Urtica  dioicd) 

Ramie  (Urtica  nivca) 

Fibre  of  paper  mulberry 

Sunn  hemp  (Crotahiria  iunced)  

4 

2 

5 
5 
10 

2 
1.2 

i-5 

3 

Broonygrass  (Sarothamnus  vulgario). 
Feather-grass  (Spartium  funcenm}..  .  . 
Meliotits  alba               

20 

14 
14 
20 
10 
17 

7 

12 

4 

20 

8 

10 
IO 

15 

20 

16 

20 

16 
16 

IO 
12 
IO 

12 

36 
33 

20 

25 
2O 

30 

18 

20 

8 
32 
16 

20 
20 
26 
32 
32 
40 

24 
28 

13 
2O 

16 
24 

Cotton                              

Gambo  hemp  (Hisbiscus  cannabinus) 
Linden-bast  (Tilia  europ&a)  

Tute  (Corchorus  capsularis)  

Lagetta  lintearia              

SW/v  alba                          

Esparto                        

°-5 
i-3 
3 

2-5 

0.8 
5 
o-5 
i-5 
i-S 
3 

LygcFum  spurt  uni  ;  

Brotnclia  pinguin 

Phormium  tenax  (New  Zealand  flax)  .  . 
Yucca  fibre                         .        

Sanseveria  fibre      .           

Afovc  ainfricann   .  .                   

Musa  text  His  (Manila  hemp) 

2 

i-5 
i-5 
i-5 
i 
0.4 

6 

5 
3-5 
3 
3 

i 

Raphia  taetigera                                 .  .  . 

Mauritia  flexuosa                           

Coir  fibre  (Cocas  tincifera)  

2.  Classification. — Perhaps  the  most  systematic  and  complete 
enumeration  of  the  various  vegetable  fibres,  together  with  a 
rla»ification  of  their  technical  uses,  is  that  given  by  Dodge  in 
his  ''Report  on  the  Useful  Plant  Fibres  of  the  World,"  from  which 
the  following  abstract  is  taken: 

STRUCTURAL   CLASSIFICATION. 
A.   FlBROVASCULAR   STRUCTURF. 

I.  Bast  fibres. — Derived  from  the  inner  fibrous  bark  of  dicot- 
yledonous plants  or  exogens,  or  outside  growers.  Thev  are 


THE   VEGETABLE  FIBRES.  101 

composed  of  bast-cells,  the  ends  of  which  overlap  each  other,  so  as 
to  form  in  mass  a  filament.  They  occupy  the  phloem  portion 
of  the  fibrovascular  bundles,  and  their  utility  in  nature  is  to  give 
strength  and  flexibility  to  the  tissue. 

2.  Woody  fibres. 

(a)  The    stems   and   twigs   of    exogenous   plants,    simply 
stripped  of  their  bark  and  used  entire,  or  separated  into  withes 
for  weaving  or  plaiting  into  basketry. 

(b)  The  entire  or  subdivided  roots  of  exogenous  plants, 
to  be  employed  for  the  same  purpose,  or  as  tie  material,  or  as 
very  coarse  thread  for  stitching  or  binding. 

(c)  The    wood    of   exogenous    trees    easily   divisible    into 
layers  or  splints  for  the  same  purposes,  or  more  finely  divided  into 
thread-like  shavings  for  packing  material. 

(d)  The  wood  of  certain  soft  species  of  exogenous  trees, 
after  grinding  and  converting  by   chemical  means   into  wood- 
pulp,  which  is  simple  cellulose,  and  similar  woods  more  carefully 
prepared  for  the  manufacture  of  artificial  silk. 

3.  Structural  fibres. 

(a)  Derived  from  the  structural  system  of  the  stalks,  leaf- 
stems,  and  leaves,  or  other  parts  of  monocotyledonous  plants, 
or  inside  growers,   occurring  as  isolated  fibrovascular  bundles, 
and  surrounded  by  a  pithy,  spongy,  corky,  or  often  a  soft,  succu- 
lent, cellular  mass  covered  with  a  thick  epidermis.     They  give 
to  the  plant  rigidity  and  toughness,  thus  enabling  it  to  resist 
injury  from  the  elements,  and  they  also  serve  as  water- vessels. 

(b)  The  whole  stems,   or  roots,  or  leaves,   or  split  and 
shredded  leaves  of  monocotyledonous  plants. 

(c)  The  fibrous  portion  of  the  leaves  or  fruits  of  certain 
exogenous   plants   when    deprived   of   their   epidermis   and   soft 
cellular  tissue. 

B.  SIMPLE  CELLULAR  STRUCTURE. 

4.  Surface  fibres. 

(a)  The  down  or  hairs  surrounding  the  seeds,  or  seed 
envelopes,  of  exogenous  plants,  which  are  usually  contained  in 
a  husk,  pod,  or  capsule. 


102  THE   TEXTILE   FIBRES. 

(b)  Hair-like  growths,  or  tomentum,  found  on  the  surfaces 
of  stems  and  leaves,  or  on  the  leaf-buds  of  both  divisions  of  plants. 

(c)  The  fibrous  material  produced   in   the   form  of  epi- 
dermal strips  from  the  leaves  of  certain  endogenous  species,  as 
the  palms. 

5.  Pseudo-fibres,  or  jalse  fibrous  material. 

(a)  Certain  of  the  mosses,  as  the  species  of  the  sphagnum, 
for  packing  material. 

(b)  Certain  leaves  and  marine  weeds,  the  dried  substance 
of  which  forms  a  more  delicate  packing  material. 

(c)  Seaweeds  wrought  into  lines  and  cordage. 

(d)  Fungous  growths,  or  the  mycelium  of  certain  fungi 
that  may  be  applied  to  economic  uses,  for  which  some  of  the 
true  fibres  are  employed. 

The  bast  fibres  are  clearly  defined,  and  all  such  fibres  when 
simply  s  ripped  are  similar  in  form  as  to  outward  appearance, 
differing  chiefly  in  color,  fineness,  and  strength.  An  example 
of  a  fine  bast  fibre  is  the  ribbons  or  filaments  of  hemp.  The 
woody  fibres  are  only  fibrous  in  the  broad  sense,  as  their  cellulose 
is  broken  down  and  all  extraneous  matter  removed  by  chemical 
means,  as  for  the  manufacture  of  paper-pulp  or  of  artificial  silk. 
The  structural  fibres  are  found  in  many  forms  differing  widely 
from  each  other,  and  the  surface  fibres  are  still  more  varied  in 
form. 

ECONOMIC   CLASSIFICATION. 

A.  SPINNING  FIBRES. 

i.  Fabric  fibres. 

(a)  Fibres  of  the  first  rank  for  spinning  and  weaving  into 
fine  and  coarse  textures  for  wearing  apparel,  domestic  use,  or 

furnishing  and  decoration,  and  for  awnings,  sails,  etc. 
(Tin-  commercial  forms  are  cotton,  flax,  ramie,  hemp,  pineapple, 
and  New  Zealand  flax.) 

(b)  Fibres  of  the  second  rank,  used  for  burlap  or  gunny, 
cotton  bagging,  woven  mattings,  floor  coverings,  and  other  coarse 
uses.     (Commercial  examples  are  coir  and  jute.) 


THE   VEGETABLE  FIBRES.  103 

2.  Netting  fibres. 

(a)  Lace  fibres,  which  are  cotton,  flax,  ramie,  agave,  etc. 

(b)  Coarse  netting  fibres,  for  all  forms  of  nets,  and  for 
hammocks.     (Commercial    forms:     Cotton,    flax,    ramie,    New 
Zealand  flax,  agave,  etc.) 

3.  Cordage  fibres. 

(a)  Fine  spun  threads  and  yarns  other  than  for  weaving; 
cords,  lines,  and  twines.     (All  of  the  commercial  fabric  fibres, 
sunn,  Mauritius,  and  bowstring  hemps,  New  Zealand   flax,  coir, 
Manila,  sisal  hemps;   the  fish-lines  made  from  seaweeds.) 

(b)  Ropes  and  cables.     (Chiefly  common  hemp,  sisal  and 
Manila  hemps,  when  produced  commercially.) 

B.  TIE  MATERIAL  (rough  twisted). 

Very  coarse  material,  such  as  stripped  palm-leaves,  the  peeled 
bark  of  trees,  and  other  coarse  growths  used  without  preparation. 

C.  NATURAL  TEXTURES. 

1.  Tree-basts,  with  tough  interlacing  fibres. 

(a)  Substitutes   for   cloth,   prepared  by   simple   stripping 
and  pounding. 

(b)  Lace-barks,  used  for  cravats,  frills,  ruffles,  etc.,  and  for 
whips  and  thongs. 

2.  The  ribbon  or  layer  basts,  extracted  in   thin,  smooth- sur- 
faced,  flexible  strips  or  sheets.     (Cuba  bast  used  as  millinery 
material,  cigarette  wrappers,  etc.) 

3.  Interlacing  structural  fibre  or  sheaths. 

(a)  Pertaining  to  leaves  and  leaf-stems  of  palms,  such  as 
the  fibrous  sheaths  found  at  the  bases  of  the  leaf-stalks  of  the 
cocoanut. 

(b)  Pertaining  to  flower-buds.     The  natural  caps  or  hats 
derived  from  several  species  of  palms. 

D.  BRUSH  FIBRES. 

i.  Brushes  manufactured  from  prepared  fibre. 

(a)  For   soft   brushes.     (Substitutes   for   animal  bristles, 
such  as  Tampico.) 


104  THE   TEXTILE  FIBRES. 

(b)  For  hard  brushes.      (Examples:    Palmetto  fibre,  pal- 
myra, kittul,  etc.) 

2.  Brooms  and  whisks. 

(a)  Grass- like   fibres.      (Examples:     Broom-root,    broom- 
corn,  etc.) 

(b)  Bass  fibres.     (Monkey  bass,  etc.) 

3.  Very  coarse  brushes  and  brooms. 

Material  used  in  street  cleaning.     Usually  twigs  and  splints. 

E.    PLAITING  AND  ROUGH-WEAVING  FIBRES. 

1.  Used  in  hats,  sandals,  etc. 

(a)  Straw- plaits.      From    wheat,    rye,    barley,    and    rice- 
straw.     (Tuscan  and  Japanese  braids.) 

(b)  Plaits  from  split  leaves,  chiefly  palms  and  allied  forms 
of  vegetation.     (Panama  hats.) 

(c)  Plaits  from  various  materials.     (Bast  and  thin  woods 
used  in  millinery  trimmings.) 

2.  Mats  and  mattings;  also  thatch  materials. 

(a)  Commercial  mattings  from  Eastern  countries. 

(b)  Sleeping- mats,  screens,  etc. 

(c)  Thatch-roofs,     made     from    tree-basts,     palm-leaves, 
grasses,  etc. 

3.  Basketry. 

(a)  Manufactures  from  woody  fibre. 

(b)  From  whole  or  split  leaves  or  stems. 

4.  Miscellaneous  manufactures. 

Willow- ware  in  various  forms;    chair-bottoms,  etc.,  from 
splints  or  rushes. 

1  .    VARIOUS  FORMS  OF  FILLING. 

i.  Stuffing  or  Upholstery. 

(a)  Wadding,    batting,    etc.,    usually    commercially    pre- 
pared lint-cotton. 

(b)  Feather  substitutes  for  filling  cushions,  etc.;    cotton, 
seed-hairs,  tomentum  from  surfaces  of  leaves,  other  soft  fibrous 
material. 

(c)  Mattress  and  furniture  filling.     The  tow  or  waste  of 


THE   VEGETABLE  FIBRES.  105 

prepared  fibre;    unprepared  bast,   straw,   and  grasses;  Spanish 
moss,  etc. 

2.  Caulking. 

(a)  Filling  the  seams  in  vessels,  etc. ;   oakum  from  various 
fibres. 

(b)  Filling  the  seams  in  casks,  etc.;    leaves  of  reeds  and 
giant  grasses. 

3.  Stiffening. 

In  the  manufacture  of  "staff"  for  building  purposes,  and 
as  substitutes  for  cow-hair  in  plaster.  New  Zealand  flax;  pal- 
metto fibre. 

4.  Packing. 

(a)  In  bulkheads,  etc.     Coir,  cellulose  of  corn-pith.      In 
machinery,  as  in  valves  of  steam-engines;  various  soft  fibres. 

(b)  For  protection  in  transportation;    various  fibres  and 
soft  grasses;  marine  weeds;  excelsior. 

G.  PAPER  MATERIAL. 

1.  Textile  papers. 

(a)  The  spinning  fibres  in  the  raw  state;    the  secondary 
qualities  or  waste  from  spinning  mills,  which  may  be  used  for 
paper  stock,  including  tow,  jute-butts,  Manila  rope,  etc. 

(b)  Cotton  or  flax  fibres  that  has  already  been  spun  and 
woven,  but  which,  as  rags,  finds  use  as  a  paper  material. 

2.  Bast  papers. 

This  includes  Japanese  papers  from  soft  basts,  such  as 
the  paper  mulberry. 

3.  Palm  papers. 

From  the  fibrous  material  of  palms  and  similar  plants. 
Palmetto  and  Yucca  papers. 

4.  Bamboo  and  grass  papers. 

This  includes  all  paper  material  from  gramineous  plants, 
including  the  bamboos,  esparto,  etc. 

5.  Wood-pulp,  or  cellulose. 

The  wood  of  spruce,  poplar,  and  similar  "paper- pulp" 
woods  prepared  by  various  chemical  and  mechanical  processes. 


io6  THE   TEXTILE  FIBRES. 

3.  Physical  Structure  and  Properties. — Seed-hairs,  or  plumose 
fibres,  are  divided  into  thiee  morphological  classes: 

(1)  Those   consisting  of  single   cells,   one   end  of   which   is 
closed  and  tapers  to  a  point,  the  other  end  being  broken  off 
abruptly  where  it  is  torn  from  the  seed  to  which  it  was  fastened 
during  growth.     This  class  includes  the  most  important  plumose 
fibres,  such  as  cotton  and  the  vegetable  silks. 

(2)  Those  consisting  of  a  series  of  cells  joined  together  to 
form  a  continuous  fibre;    this  class  includes  the  tomentum  or 
epidermal  hair  obtained  from  certain  ferns,  and  are  practically 
valuless  as  textile  materials,  though  used  for  upholstery  and  such 
purposes. 

(3)  Those  consisting  of  several  series   of  cells,   represented 
by  the  fibres  of  the  so-called  cotton-grass  and  elephant- grass. 

The  cell-wall  of  the  plumose  fibres  in  some  cases  is  relatively 
thin,  while  in  others  it  is  comparatively  thick.  It  is  generally 
without  apparent  structure,  though  sometimes  it  is  seen  to  con- 
tain pores,  and  occasionally  a  mesh-like  interlacing  of  filaments 
is  observable,  especially  at  the  base  of  the  fibre.  The  inner 
surface  of  the  cell-wall  is  usually  coated  with  a  cuticule  of 
dried  protoplasm,  which  is  evidently  similar  in  constitution  to 
the  outer  cuticule,  as  it  also  remains  undissolved  when  the  fibre 
is  dissolved  in  either  concentrated  sulphuric  acid  or  an  ammo- 
niacal  solution  of  copper  oxide.  The  general  term  of  the  bast 
fibre  includes  really  two  distinct  forms;  if  the  fibre  occurs  in 
the  bast  itself  it  should  be  designated  as  true  bast  fibres,  such  as 
linen,  hemp,  and  jute.  When,  however  the  fibres  occur  not  in 
the  bast,  but  in  single  bundles  in  the  leaf  structure  of  the  plant, 
they  should  be  designated  as  sclerenchymous  fibres.  In  true  bast 
fibres  there  are  seldom  to  be  noticed  distinct  pores,  whereas 
the  sclerenchymous  fibres  are  abundantly  supplied  with  them. 
On  the  other  hand,  however,  the  true  bast  fibres  frequently 
show  peculiar  dislocations  or  joints  caused  by  an  unequal  cell- 
pressure  in  the  growing  plant;  these  are  entirely  absent  in  the 
nchymous  fibres.  The  ends  of  all  bast  fibres  are  usually 
quite  characteristic  and  exhibit  a  wide  diversity  of  forms;  at 
times  they  are  sharp-pointed  and  again  blunt;  some  possess 


THE   VEGETABLE  FIBRES.  107 

but  a  single  point,  while  others  are  split  or  forced;  sometimes 
the  <:ell-wall  is  thicker  than  in  the  rest  of  the  fibre,  and  sometimes 
it  is  thinner.  When  the  cells  occur  in  bundles  they  are  frequently 
separated  from  one  another  by  a  so-called  median  layer,  which 
forms  a  sort  of  matrix  in  which  the  separate  filaments  are  imbedded. 
This  layer  usually  differs  in  its  chemical  composition  from  the 
cell-wall  proper,  and  gives  different  color  reactions  with  various 
reagents,  as  it  generally  consists  of  lignified  tissue.  In  many 
cases  the  cell- walls  appear  to  have  a  distinct  structure,  being 
composed  of  concentric  layers  which  in  cross-section  exhibit  a 
stratified  appearance. 

Although  cellulose  forms  the  chief  constituent  of  all  vegetable 
fibres,  it  varies  much  in  its  purity  and  associated  products  in 
its  occurrence  in  the  various  fibres.  Seed-hairs  like  cotton  con- 
sist almost  entirely  of  cellulose  in  a  rather  pure  state,  but  the 
bast  and  vascular  fibres  always  contain  more  or  less  alteration 
products  of  cellulose,  chief  among  which  is  ligno- cellulose  or 
lignin;  in  fact,  jute  is  almost  entirely  composed  of  this  latter 
substance.  Seed-hairs  consist  of  one  single  cell  to  the  individual 
fibre  and  have  very  little  foreign  or  incrusting  material  present. 
The  other  fibres  are  made  up  of  an  aggregation  of  cells  bound 
together  in  a  compact  form,  and  in  the  cell  interstices  there  is 
always  present  more  or  less  gummy  and  resinous  matter,  oils, 
mineral  matter,  and  lignified  tissue.  All  vegetable  fibres  appear 
to  contain  more  or  less  pigment  matter,  usually  of  a  slight  yellowish 
or  brownish  color.  In  ordinary  cotton  and  ramie  this  coloring- 
matter  occurs  in  only  a  very  small  amount  and  the  natural  fibre 
is  quite  white  in  appearance.  There  are  some  varieties  of  cotton, 
however,  which  are  distinctly  brown  in  color.  Flax,  jute,  hemp, 
etc.,  contain  a  considerable  amount  of  pigment  and  are  of  a 
brownish  color  more  or  less  pronounced. 

Besides  cellulose  and  lignin,  there  is  also  present,  especially  in 
seed-hairs,  a  cutose  membrane  (cork-tissue)  in  the  form  of'  an 
external  cuticle.  Cutose  is  very  insoluble  in  concentrated  sul- 
phuric acid,  but  is  partially  soluble  in  boiling  potash.  It  doubt- 
less originates  from  the  plant-wax  which  is  imbedded  in  the  cell. 
Albuminous  matter  also  occurs  in  the  fibre  elements,  mostly  as  a 


lo8  THE   TEXTILE  FIBRES. 

dried  tissue  which  fills  the  lumen  of  the  fibre  more  or  less  com- 
pletely. It  also  occurs  as  a  thin  film  which  coats  the  inner  wall 
of  the  cell,  and  remains  undissolved  when  the  fibre  is  treated  with 
concentrated  sulphuric  acid.  This  membrane  exhibits  all  the 
reactions  of  albumin.  Silicic  acid  sometimes  is  present  in  vege- 
table fibres,  but  only  in  the  walls  of  the  stegmata  and  in  epidermal 
cells.  On  ignition  the  silicious  matter  is  left  in  almost  the 
original  form  of  the  fibre.  The  silicious  skeleton  is  insoluble  in 
hydrochloric  acid,  whereas  the  rest  of  the  ash  is  readily  dissolved 
by  this  reagent.  Crystals  of  calcium  oxalate  occasionally  occur 
in  some  fibres;  they  are  insoluble  in  acetic  but  dissolve  in  hydro- 
chloric acid.  On  ignition  of  the  fibres  these  crystals  are  con- 
verted into  calcium  carbonate  without  much  change  of  form,  and 
then  are  soluble  in  even  very  dilute  acids. 

All  plant- cell  membranes  are  doubly  refractive  towards  light, 
and  this  is  especially  true  of  thick-walled  cells  which  are  parallel 
to  the  fibre  proper.  If  such  a  fibre  is  examined  in  the  dark  field 
of  a  micro-polariscope  it  shows  a  beautiful  arrangement  of  bright 
prismatic  colors. 

In  color  the  vegetable  fibres  vary  considerably  in  the  raw  state; 
some,  like  cotton,  ramie,  and  the  vegetable  silks,  are  almost 
pure  white.  Others,  like  tinen,  possess  a  grayish  brown  color; 
while  others  yet,  like  jute  and  hemp,  have  a  decided  brown  color. 
These  colors,  however,  are  due  to  incrusting  impurities,  as  the 
cellulose  fibres,  purified  and  freed  from  all  such  foreign  matters, 
are  always  white. 

In  lustre  the  vegetable  fibres  are  usually  below  those  of  animal 
origin,  and  especially  silk,  though  they  differ  much  in  this  respect. 
Cotton  probably  has  the  least  lustre  of  any,  as  its  external  surface 
is  by  no  means  smooth  and  even,  but  presents  a  wrinkled  and 
creased  appearance,  hence  scatters  the  rays  of  light  reflected 
therefrom.  The  other  plumose  fibres,  as  the  various  vegetable 
silks,  have  a  very  smooth  surface,  and  consequently  exhibit 
considerable  lustre.  Linen,  jute,  ramie,  and  the  bast  fibres  in 
general,  when  decorticated  to  their  fine  filaments,  and  properly 
freed  from  all  incrusting  matter,  possess  a  rather  high  degree  of 
lustre;  for  though  they  have  more  or  less  roughened  places  and 


THE   VEGETABLE  FIBRES. 


109 


irregularities  on  their  external  surface,  the  majority  of  such 
surface  is  smooth  and  regular. 

The  more  closely  the  fibre  approximates  to  pure  cellulose, 
the  greater  becomes  its  flexibility  and  elasticity;  and  the  more  it  is 
lignified  the  less  these  qualities  become.  That  is  to  say,  the 
highly  lignified  fibres  are  stiff  and  brittle,  and  but  little  adapted 
to  the  spinning  of  fine  yarns. 

The  hygroscopic  moisture  contained  in  vegetable  fibres  is 
considerably  lower  than  that  present  in  either  wool  or  silk.  While 
the  latter  fibres  under  normal  atmospheric  conditions  will  aver- 
age as  much  as  12  to  18  per  cent,  of  moisture,  cotton  and  linen  will 
have  only  from  6  to  8  per  cent.  The  following  table  (after  Wies- 
ner)  gives  the  amount  of  moisture  in  various  vegetable  fibres 
in  the  ordinary  air-dry  condition,  and  also  the  greatest  amount 
they  will  absorb  hygroscopically : 

HYGROSCOPIC  MOISTURE  IN  VEGETABLE  FIBRES. 


Fibre. 

Air-dry 
Condition. 

Maximum 
Amount 
Hygroscopic 
Water. 

Cotton. 

6  66 

20  oo 

Flax  '  Belgian)  

5  70 

13   OO 

Tute.  . 

6  oo 

23    3O 

China  grass  

6    C2 

18  i? 

Manila  hemp  

12.  «;o 

40.00 

Sunn  hemp  

r  .  31 

10.87 

Hibiscus  cannabinus 

7    38 

14   6l 

Abelmoschus  tetraphyllos.  ... 

6  80 

I  3    OO 

Esparto  .    . 

6  o? 

13    32 

7   02 

1^    2O 

'       ~. 

o  26 

16.08 

Sida  retiisci 

74Q 

17    II 

Aloe  perfolidta 

6  QC 

18  03 

Bromelia  karatas  .  .        .                ... 

6  82 

18  io 

TJiespesia  lampas  

10  8-? 

j.u.  *y 

18.  io 

Cordia  lati  folia  

j.w.«jj 
8  03 

l8.22 

"•vo 
7.84 

IO.  12 

Tillandsia  fibre  :  

9  .00 

20.  50 

Pita  

12     3O 

30.00 

Calotropio  giganiea  (bast)  ...            .            .    . 

S    6? 

13.13 

CHAPTER   IX. 
COTTON. 

i.  Origin  and  Growth. — The  use  of  cotton  as  a  textile  fibre 
dates  back  to  antiquity,  mention  of  it  being  found  in  the  writings 
of  Herodotus  (445  B.C.).  It  was  used  in  India,  Egypt,  and  China. 
The  first  European  country  to  make  cotton  goods  appears  to 
have  been  Spain. 

The  cotton  fibre  consists  of  the  seed-hairs  of  several  species 
of  the  genus  Gossypium,  belonging  to  the  natural  order  of  Mal- 
•vacea. 

The  cotton  plant  is  a  shrub  which  reaches  the  height  of  4  to 
6  ft.  It  is  more  or  less  indigenous  to  nearly  all  sub-tropical 
countries,  though  it  appears  to  be  best  capable  of  cultivation  in 
warm,  humid  climates  where  the  soil  is  sandy,  and  in  the  neighbor- 
hood of  the  sea,  lakes,  or  large  rivers.  It  appears  to  thrive  most 
readily  in  North  and  South  America,  India,  and  Egypt;  it  has 
also  been  cultivated  in  Australia,  but  not  as  yet  with  any  great 
degree  of  success;  inferior  qualities  have  been  grown  along  the 
coasts  of  Africa;  that  grown  in  Europe  (Italy  and  Spain)  is  prac- 
tically negligible,  as  far  as  commercial  considerations  arc  con- 
cerned. In  America,  India,  and  Egypt  the  cotton  plant  is  annual 
in  its  growth,  but  in  hot  tropical  climates,  and  in  South  America, 
it  becomes  a  perennial  plant,  and  assumes  more  of  a  tree-like 
form.  The  leaf  of  the  cotton  plant  has  three-pointed  l.>l>es; 
the  flower  has  five  petals,  yellow  at  the  base,  but  becoming  almost 
white  at  the  edges.  The  fruit  of  the  cotton  plant  forms  the  cotton 
boll,  which  contains  the  seeds  with  the  attached  fibres.  The 
boll  consists  of  from  three  to  five  segments,  and  on  ripening 

no 


COTTON.' 


in 


bursts  open  and  discloses  a  mass  of  pearly  white  downy  fibres 
(Fig.  30),  in  which  are  imbedded  the  brownish  black  to  black- 
colored  cottonseeds.  *  The  cotton  boll  should  be  picked  as  soon 
as  possible  after  ripening;  the  seeds  are  then  separated  from  the 
fibres  by  a  process  known  as  ginning.  *  Besides  the  fibre  itself, 
nearly  all  of  the  other  products  of  the  cotton  are  now  utilized 
commercially.  The  seeds  are  of  especial  value,  as  they  contain  a 


FIG.  30.— Sections  of  the  Cotton  Boll  (Egyptian).     (Witt.) 
A,  stem;  B,  calyx;  C,  capsule;  D,  seed;  E,  cotton  fibre. 

large  quantity  of  oil,  which  is  expressed  and  used  for  soap-making 
and  many  other  purposes,  while  the  residuum  of  meal  and  hulls 
is  converted  into  cattle  foods  and  fertilizer.  The  short  fibres, 
or  nep,  left  on  the  seed  after  the  first  ginning,  are  also  recovered 
by  a  second  process  and  used  in  the  manufacture  of  lint  and 
cotton-batting.  The  separation  of  seed  particles  from  the  fibre 
is  not  always  perfect,  and  they  frequently  make  their  appearance 
in  gray  calico  in  the  form  of  black  specks  or  motes,  and  as  these 


112  THE   TEXTILE  FIBRES. 

contain  small  quantities  of  oil  and  tannin  matters  which  are  pressed 
out  into  the  surrounding  fibres,  they  cause  specks  and  uneven- 
ness  in  dyeing  and  finishing.  If  they  come  in  contact  with  solu- 
tions or  materials  containing  iron  compounds,  a  violet  stain  will 
be  produced,  the  color  of  which,  however,  may  not  develop  for 
some  months. 

Bowman  (loc.  cit.)  gives  an  excellent  description  of  the 
physiological  development  of  the  cotton  fibre,  from  which  the 
following  is  quoted:  "In  their  earliest  stages  the  young  cotton 


FIG.  31. — Typical  Cotton  Fibres. 

A,  normal  fibre  showing  regular  twists;    B,  straight  fibre  without  twists; 
C,  a  knot  or  irregularity  in  growth  of  fibre. 

fibres  appear  to  have  a  circular  section  arising  from  the  com- 
parative thickness  of  the  tube- walls;  but  as  these  walls  gradually 
become  thinner  by  the  longitudinal  growth  of  the  hair  and  the 
pressure  to  which  they  are  subjected  by  the  contact  of  surround- 
ing fibres  enclosed  within  the  pod,  they  gradually  become  flat- 
tened, and  just  before  the  pod  bursts  the  outer  walls  of  the  cells 
have  become  so  attenuated  in  the  longest  fibres  as  to  be  almost 
invisible  even  under  high  microscopic  powers,  and  present  the 
appearance  of  a  thin,  pellucid,  transparent  ribbon.  With  the 
burning  of  the  pod,  however,  a  change  occurs.  The  admission 
of  air  and  sunlight  causes  a  gradual  unfolding  of  the  hairy  plexus, 
and  the  rapid  consolidation  of  the  liquid  cell  contents  on  the 
inner  surface  of  the  cell-wall  gives  them  a  greater  thickness  and 


COTTON.  113 

density,  which  is  further  increased  by  the  gradual  shrinking 
in  of  the  walls  themselves  upon  the  cell  contents.  There  is 
also  a  gradual  rounding  and  thickening  of  the  fibre,  which  in- 
creases by  the  deposition  of  matter  on  the  inner  wall  of  the  cell. 
As  this  action  is  not  perfectly  uniform,  arising  from  the  unequal 
exposure  of  different  parts  of  the  fibres  to  light  and  air,  it  causes 
a  twisting  of  the  hairs,  which  is  always  a  characteristic  of  cotton 
when  viewed  under  the  microscope,  and  the  flat  collapsed  por- 
tions of  the  tube  form  so  many  reflecting  surfaces,  to  which  the 


FIG.  32.— Typical  Cotton  Fibres. 

A,  broad,  flat  fibre  near  the  base;   B,  thick  rounded  fibre;   C,  fibre  near  the 
pointed  end;  D,  cut  end  of  fibre. 

brightness  of  the  fibre  when  stretched  tight  in  the  fingers  is  no 
doubt  due.  Another  change  also  occurs  at  this  stage,  a  change 
which  corresponds  to  the  ripening  of  fruit.  In  the  earliest  period 
of  their  formation  the  growing  cells  are  filled  with  juices  which 
are  more  or  less  astringent  in  character.  Under  the  influence 
of  light  and  air  these  cell  contents  undergo  a  chemical  change, 
in  which  the  astringent  principles  are  replaced  by  more  or  less 
saccharine  or  neutral  juices,  until  in  the  perfectly  ripe  cotton 
fibre  the  cell-walls  are  composed  of  almost  pure  cellulose. 

The  cell-wall  of  the  cotton  is  thin  in  comparison  with  that  of 
the  bast  fibres,  but  in  comparison  with  the  other  seed- hairs  it 
is  remarkably  thick.  This  accounts  for  its  much  greater  strength 


OF  THE 

UNIVERSITY 


114  77/£   TEXTILE  FIBRES. 

over  the  latter.  In  completely  developed  fibres,  the  thickness 
of  the  cell-wall  is  from  one-third  to  two-thirds  of  the  total  thick- 
ness of  the  fibre  itself. 

The  quality  of  the  cotton  fibre  depends  not  only  on  the  species 
of  the  plant  from  which  it  is  derived,  but  also  on  the  manner 
of  its  cultivation.  The  conditions  which  exercise,  perhaps, 
the  greatest  influence  are  :  (a)  the  seed,  (b)  the  soil,  (c)  the  mode 
of  cultivation,  (d)  the  climatic  conditions.  The  seed  for  sowing 
must  be  carefully  and  specially  chosen  for  the  purpose.  A 
very  dry  soil  produces  harsh  and  brittle  cotton,  the  fibres  of 
which  are  very  irregular  in  length;  a  moist  and  sandy  soil  pro- 
duces a  very  desirable  cotton  of  long  and  fine  staple.  The  best 
soil  is  considered  to  be  a  light  loam,  while  a  damp  clay  is  regarded 
as  the  worst.  Soils  situated  in  proximity  to  the  sea,  and  there- 
fore containing  considerable  saline  matter,  appear  to  furnish 
the  most  valuable  varieties  of  cotton,  and  it  is  claimed  that  the 
saline  constituents  of  the  soil  have  considerable  influence  on 
the  growth  and  development  of  the  cotton  fibre. 

2.  Varieties  of  Cotton.  —  The  classification  of  the  different 
species  of  cotton  plant  varies  with  different  authorities;  the  most 
comprehensive,  perhaps,  is  to  classify  the  different  varieties  of 
the  cotton  plant  as  (i)  the  tree,  (2)  the  shrub,  and  (3)  the 
herbaceous  species.*  According  to  Parlatore  all  commercial 

*  The  following  list  of  species  of  the  cotton-plant  are  more  or  less  recognized 
by  botansists: 

G.  album  Hamilton,  a  synonym  of  G.  herbaceum;    commercially  known  as 

upland  cotton;    has  a  white  seed. 
G.  arboreum  Linn.,  a  tree-like  plant;    perennial;    indigenous  to  India;    pro- 

duces but  little  fibre. 
G.  barbadense    Linn.,   indigeneous  to  America  and    outlying    islands;    gives 

the  highly  prized  sea-island  cotton. 
G.  brasiliense  Macfad.,  a  tropical  species;    belongs  to  the  so-called  "kidney- 

cottons";   the  seeds  adhere  to  one  another  in  clusters. 
G.  chinense  Fisch.  &  Otto,  a  synonym  for  G.  herbaceum;   a  Chinese  cotton. 
G.  croceum  Hamilton,  a  synonym  for  G.  herbaceum;   possesses  a  yellow  lint. 
G.  eglandulosum  Cav.,  a  synonym  for  G.  herbaceum. 
G.  datum  Salisb.,  a  synonym  for  G.  herbaceum. 
G.  jructescens  Lasteyr.,  a  synonym  for  G.  barbadense. 
G.  fuscum  Roxb.,  a  synonym  for  G.  barbadense. 
G.  glabrum  Lam.,  a  synonym  for  G.  barbadense. 
G.  glanduhsum  Stend.,  a  synonym  for  G.  herbaceum. 


COTTON.  115 

cotton  is  derived  from  seven  species  of  the  Gossypium,  which  he 
enumerates  as  follows: 

(i)  G.  barbadense,  which  comprises  the  long- stapled  and 
silky-fibred  cottons  known  as  Barbadoes,  Sea-island,  Egyptian, 
and  Peruvian.  The  plant  reaches  a  height  of  from  6  to  8  ft., 

G.  herbaceum  Linn.,  usually  considered  of  Asiatic  origin;    synonymous  with 

G.  hirsutum;   ordinary  upland  cotton. 

G.  hirsutum  Linn.,  of  American  origin;  Georgia  upland  cotton. 
G.  indicum  Lam.,  a  synonym  for  G.  herbaceum. 

G.  jamaicense  Macfad.,  a  synonym  for  G.  barbadense;   grows  in  Jamaica. 
G.  javanicum  Blume,  a  synonym  for  G.  barbadense;    grows  in  Java. 
G.  lati/olium  Murr.,  a  synonym  for  G.  herbaceum. 
G.  leonimum  Medic.,  a  synonym  for  G.  herbaceum. 
G.  macedonicum  Murr.,  a  synonym  for  G.  herbaceum. 
G.  maritimum  Tod.,  a  synonym  for  G.  barbadense. 
G.  micranthum  Cav.,  a  synonvm  for  G.  herbaceum. 
G.  molle  Mauri,  a  synonym  for  G.  herbaceum. 
G.  nanking  Meyen,  a  synonym  for  G.  herbaceum. 
G.  neglectum  Tod.,  indigenous  to  India;    similar  to  G.  arboreum]    extensively 

grown  in  India;   gives  the  Dacca  and  China  cottons. 
G.  nigrum  Hamilton,  a  synonym  for  G.  barbadense. 
G.  obtusifolium  Roxb.,  a  synonym  for  G.  herbaceum. 
G.  oligospermum  Macfad.,  a  synonym  for  G.  barbadense. 
G.  paniculatum  Blanco,  a  synonym  for  G.  herbaceum. 
G.  perenne  Blanco,  a  synonym  for  G.  barbadense. 
G.  peruvianum  Cav.,  a  synonym  for  G.  barbadense. 
G.  punctatum  Schum.  &  Thonn.,  a  synonym  for  G.  barbadense. 
G.  racemosum  Poir,  a  synonym  for  G.  barbadense. 
G.  religiosum  Par.,  a  synonym  for  G.  arboreum;    so-called  because  its  use  is 

mostly  restricted  to  making  turbans  for  Indian  priests;    also  because  it 

grows  in  the  gardens  of  the  temples;    it  has  the  cultural  name  of  Nurma 

or  Deo  cotton.     Also  a  variety  of  G.  barbadense. 
G.  roxburghianum  Tod.,  a  variety  of  G.  neglectum;  corresponds  to  the  Dacca 

cotton  of  India. 

G.  siamense  Tenore,  a  synonym  for  G.  herbaceum. 
G.  sinense  Fisch.,  a  synonym  for  G.  herbaceum. 
G.  stocksii  Masters,  a  synonym  for  G.  herbaceum;   claimed  to  be  the  original 

of  all  cultivated  forms  of  this  latter  species. 
G.  strictum  Medic.,  a  synonym  for  G.  herbaceum. 
G.  tomentosum,  indigenous  to  the  Sandwich  Islands;    the  bark  is  used  for 

making  twine. 

G.  tricuspidatum  Lam.,  a  synonym  for  G.  herbaceum. 
G.  vitijolium  Lam.,  a  synonym  for  G.  barbadense. 
G.  vitijolium  Roxb.,  a  synonym  for  G.  herbaceum. 
G.  u'ightiannm  Tod.,  a  synonvm  for  G.  lierbaceum;   claimed  by  Todaro  to  be 

the  primitive  forms  of  the  Indian  cottons. 


1 10  THE   TEXTILE  FIBRES. 

and  has  yellow  blossoms.  Owing  to  variations  in  the  conditions 
of  its  cultivation,  however,  the  present  sea-island  cotton  has 
changed  considerably  from  the  original  barbadense.  This 
variety  is  employed  for  the  spinning  of  fine  yarns,  such  as  are 
known  in  trade  as  "Bolton  counts." 

(2)  G.  herbaceum,  including  most  of  the  cotton  from  India, 
southern  Asia,  China,  and  Italy.     It  is  an  annual  plant  growing 
from  5  to  6  ft.  in  height ;  unlike  the  barbadense  variety,  its  seeds 
are  generally  covered  with  a  soft   undergrowth   of   fine  down, 
which  is  an  objectionable  feature.     The  flower  is  yellow  in  color. 
This  species  is  perhaps  the  hardiest  of  the  cottons,  and  is  cultivated 
over  a  wider  range  of  latitude.     It  forms  the  source  of  nearly  all 
the  Indian  cotton.-     It  is  used  for  the  spinning  of  low- count 
yarns,  also  for  the  making  of  condenser  yarns  for  the  manufac- 
ture of  flannelettes. 

(3)  G.    hirsutum,    including   most    of   the    cotton    from    the 
southern   United   States,   also   known   as   upland   cotton.     The 
plant   is   shrubby   in   appearance,   seldom   reaching   more    than 
7  ft.  in  height;    like  the  preceding  variety,  the  seeds  are  also 
covered  with  a  fine  undergrowth  of  down. 

(4)  G.  arboreum,  including  the  cotton  from  Ceylon,  Arabia, 
etc.     As  the  name  indicates,  it  is  a  tree- like  plant,  and  grows 
from  12  to  18  ft.  in  height.     The  fibres  are  of  a  greenish  color 
and  very  coarse;  its  flowers  are  of  a  reddish  color. 

(5)  G.  peruvianum,  including  the  native  Peruvian  and  Bra- 
zilian cottons.     This  differs  from  other  varieties  of  cotton  in  that 
it  is  a  perennial  plant ;  the  growth  from  the  second  and  third  years, 
however,  only  is  utilized. 

(6)  G.  tahitense,  found   chiefly  in  Tahiti  and    other  Pacific 
islands. 

(7)  G.  sandwichense,  occurring   principally  in  the  Sandwich 
Islands. 

This  classification  is  claimed  to  include  all  the  commercial 
varieties  of  cotton;  it  is  probable,  however,  that  the  last  two  can 
be  included  under  the  barbadense  and  hirsutum  varieties,  as 
they  possess  the  same  characteristics  as  these  fibres. 

Other  authorities  on  the  botany  of  the  cotton  plant  have  rec- 


COTTON.  117 

ognized  many  more  species  than  those  above  described.  Agos- 
tino  Todaro  has  described  52  varieties,  while  the  Index  Kewensis 
records  42  distinct  species  and  refers  to  88  others  which  it  classi- 
fies as  synonyms.  Hamilton  reduces  the  number  of  species  to 
three,  namely,  the  white- seeded,  black-seeded,  and  yellow-linted, 
assigning  to  these  species  the  botanical  names  album,  nigrum, 
and  croceum.  The  chief  difficulty  experienced  in  the  botanical 
classification  of  the  cotton  plant  is  the  fact  that  it  hybridizes  very 
readily  and  has  a  tendency  to  suffer  alteration  in  variety  with 
change  in  the  conditions  of-  its  cultivation  or  variation  in  the 
character  of  the  soil  or  climate. 

Besides  the  varieties  of  cotton  above  enumerated,  which  are 
practically  all  which  find  any  important  commercial  application, 
there  is  another  plant  which  yields  a  fibre  somewhat  similar  to 
cotton,  and  known  as  the  silk-cotton  plant.  It  belongs  to  the 
same  natural  order,  Malvacea,  as  the  ordinary  cotton  plant,  but 
is  of  a  different  genus,  being  Salmalia  instead  of  Gossypium.  It 
grows  principally  on  the  African  coast  and  in  some  parts  of 
tropical  Asia.  The  plant  is  rather  a  large  tree,  reaching  from 
70  to  80  ft.  in  height.  The  blossoms  are  red  in  color,  and  the 
seeds  are  covered  with  long  silky  fibres,  which  are  not  adapted, 
however,  for  spinning. 

Although  fibres  from  the  different  species  of  the  cotton-plant 
all  possess  the  same  general  physical  appearance,  nevertheless 
there  are  characteristic  features  in  each  worthy  of  careful  obser- 
vation. 

Gossypium  barbadense:  Sea-island.  —  This  constitutes  the 
most  valuable,  perhaps,  of  all  the  different  species.  Its  chief 
points  of  superiority  are  (a)  its  length,  being  more  than  half  an 
inch  longer  than  the  average  of  other  cottons;  (b)  its  fineness  of 
staple;  (c)  its  strength;  (d)  its  number  of  twists,  which  allow 
it  to  be  spun  to  finer  yarns;  (e)  its  appearance,  it  being  quite 
soft  and  silky.  It  is  also  characterized  by  a  light-cream  color. 
Sea- island  cotton  is  mostly  used  for  the  production  of  fine  yarns 
ranging  from  i2o's  to  3oo's;  it  is  said  that  as  fine  as  2ooo's  has 
been  spun  from  it.*  On  account  of  its  adaptability  for  mercer- 

*  The  "count"  of  cotton  yarn  means  the  number  of  hanks  of  840  yards  each 


Ii8  THE   TEXTILE  FIBRES. 

izing  it  is  also  largely  employed  for  this  purpose,  in  which  case 
much  coarser  yarns  are  often  prepared  from  it.  Owing  to  the 
wide  cultivation  of  sea- island  cotton  at  the  present  time,  for  its 
growth  is  no  longer  strictly  confined  to  the  islands  of  the  sea,  it  is 
difficult  to  make  a  definite  statement  as  to  its  length  of  staple,  as 
this  will  vary  considerably  with  the  method  and  place  of  cultiva- 
tion. The  maximum  length,  however,  may  be  taken  as  2  ins.,  and 
the  minimum  as  i  J  ins.,  with  a  mean  of  if  ins.  Florida  sea-island 
cotton  is  very  similar  in  general  characteristics  to  sea -island 
proper,  possessing  about  the  same  mean  length  of  staple,  but  being 
somewhat  less  in  the  maximum  length.  Both  of  these  varieties 
of  sea-island  show  a  maximum  diameter  of  0.000714  in.,  a 
minimum  of  0.000625  in.,  and  a  mean  of  0.000635  in.  Fiji 
sea-island  is  less  regular  in  its  properties  than  the  two  preceding 
varieties,  and  though  its  maximum  length  is  somewhat  greater 
than  sea-island  itself,  yet  the  mean  length  is  about  the  same,  as 
is  also  the  diameter.  This  cotton,  however,  has  a  very  irregular 
staple  and  contains  a  large  percentage  of  imperfect  fibres,  which 
causes  the  waste  to  be  rather  high.  The  number  of  twists  in  the 
fibre  is  also  less  and  does  not  occur  as  regularly.  Gallini  Egyptian 
cotton  is  sea-island  cotton  grown  in  Egypt.  It  is  somewhat 
inferior  to  the  American  varieties  in  general  properties.  It  pos- 
sesses a  yellowish  color  which  distinguishes  it  from  the  product 
of  all  other  countries.  The  maximum  length  of  the  fibre  is  if 
ins.,  the  minimum  i  J  ins.,  and  the  mean  i  J  ins.  The  fibres  differ 
very  little  in  their  diameter,  the  average  being  0.000675  in. 
Peruvian  sea-island  is  somewhat  coarser  in  structure  than  the 
sea-island  proper,  being  more  hairy  in  appearance;  it  has  a 

contained  in  i  Ib.  The  size  120*5,  for  instance,  means  cotton  yarn  of  such 
fineness  that  120  hanks  of  840  yards  (=  100,800  yards)  weigh  i  Ib.  The  French 
method  of  numbering  is  based  on  the  decimal  system,  and  the  count  means 
the  number  of  hanks  each  1000  meters  in  length  required  to  weigh  500  grams.  In 
order  to  change  from  French  to  English  count,  multiply  the-  former  by  0.847, 
or  JJ.  The  Belgian  method  of  counting  is  to  use  the  number  of  <H4o-yur<l  hanks 
in  500  grams.  The  Austrian  system  is  the  number  of  hanks  of  950  ells  each  •  <>n- 
t.iim-d  in  500  grams.  The  English  system  is  the  one  mostly  used,  being  employed 
in  England,  America,  India,  Germany,  Italy,  and  Switzerland,  and  even  in  parts 
of  Austria. 


COTTON.  119 

slight  golden  tint.  In  staple  it  varies  from  if  ins.  in  length  to 
if  ins.,  with  a  mean  of  ij  ins.  Tahiti  sea-island  resembles  the 
Fiji  variety  very  closely;  it  has  a  creamy  color.  The  length  of 
staple  varies  from  i  J  to  i }  ins.,  with  a  mean  of  ij  ins.  It  shows  a 
considerable  percentage  of  imperfect  fibres  due  to  a  short  under- 
growth on  the  seed.  Its  average  diameter  is  0.0x^0641  in. 

Gossypium  herbaceum. — Smyrna  cotton  is  grown  principally 
in  Asiatic  Turkey.  It  has  a  rather  characteristic  appearance 
under  the  microscope,  being  very  even  in  its  diameter  but  irregu- 
lar in  its  twist,  showing  many  fibres  where  the  twist  is  almost 
entirely  absent.  In  length  the  staple  varies  from  ij  to  J  ins., 
with  a  mean  of  i  in.;  the  mean  diameter  is  about  0.00077  in. 
Brown  Egyptian  cotton  is  supposed  to  be  indigenous  to  that 
country.  It  is  characterized  by  a  fine  golden  color,  and  great 
toughness  and  tensile  strength.  It  is,  however,  shorter  and 
coarser  than  the  Gallini  cotton.  In  length  of  staple  it  varies 
from  i£  to  i|  ins.,  with  a  mean  of  1.31  ins.;  the  mean  diameter 
is  0.000738  in.  African  cottons  are  all  derived  from  the  her- 
baceum species.  These  cottons  have  a  slight  brownish  tint, 
and  always  contain  a  large  amount  of  short  fibre.  The  fibres 
also  vary  much  in  diameter  and  thickness  of  the  tube-walls,  and 
many  exhibit  a  transparent  appearance  under  the  microscope. 
Yarns  made  from  these  cottons  are  always  uneven  on  the  surface. 
The  length  of  staple  varies  from  i^  to  J  ins.,  with  an  average  of 
1.03  ins.;  the  mean  diameter  is  0.00082  in.  Hingunghat  cottons 
are  Indian  varieties;  the  quality  of  these  varies  with  the  soil  and 
climate  of  the  province  in  which  they  are  grown.  As  a  rule, 
they  are  of  rather  inferior  grade;  the  best  variety  is  the  Surat 
cotton.  Under  the  microscope  the  Hingunghat  cotton  shows 
much  variation  in  diameter,  although  it  possesses  fewer  twists 
than  the  better  grades  of  cotton,  yet,  unlike  the  African  varieties, 
it  shows  very  few  fibres  without  any  convolutions  at  all.  In 
length  of  staple  it  varies  from  iT3T  to  J  ins.,  with  a  mean  of  1.03  ins. ; 
the  average  diameter  is  0.00084  in.  Broach,  Tinnevelly,  Dharwar, 
Oomrawuttee,  Dhollerah,  Western  Madras,  Comptah,  Bengal,  and 
Scinde  are  other  varieties  of  Indian  cotton,  all  belonging  to  the 
herbaceum  species.  They  have  the  same  general  properties  and 


120  THE   TEXTILE  FIBRES. 

staple  as  the  preceding,  becoming  more  and  more  inferior,  how- 
ever, in  the  order  of  the  list  given. 

Gossypium  hirsutum. —  White  Egyptian,  unlike  the  brown 
variety  described  above,  is  not  indigenous,  but  was  transplanted 
from  America.  In  length  of  staple  it  varies  from  if  to  ij  ins., 
with  a  mean  of  i^  ins.;  the  diameter  averages  0.00077  in.  This 
cotton  shows  a  large  number  of  fibres  having  but  a  partially 
developed  spiral  form.  Orleans  cotton  is  the  typical  American 
variety,  and  is  perhaps  the  best  of  the  American  cottons.  The 
fibres  are  quite  uniform  in  length,  having  an  average  staple  of 
about  i  in.  and  a  mean  diameter  of  0.00076  in.  It  is  almost 
pure  white  in  color.  Texas  cotton  much  resembles  the  fore- 
going, but  has  a  slight  golden  color;  its  length  and  diameter  of 
staple  are  the  same.  Upland  cotton  is  another  very  similar  variety; 
its  length  of  staple,  however,  is  somewhat  less  than  the  foregoing, 
averaging  but  iJ  in.  Its  twist  is  rather  inferior  to  the  Orleans, 
and  it  shows  a  larger  number  of  straight  fibres.  Mobile  cotton 
is  the  most  inferior  of  the  American  varieties;  it  varies  in  length 
of  staple  from  i  to  J  in.,  with  a  mean  of  J  in. ;  its  average  diameter 
is  0.00076  in.  It  shows  about  the  same  microscopic  appearance 
as  upland  cotton.  Santos  cotton  comes  from  Brazil;  it  is  not 
much  in  demand  on  account  of  its  inferior  quality. 

Gossypium  peruvianum. — Rough  Peruvian;  this  cotton  has  a 
light  creamy  color  and  is  rather  harsh  and  hairy  in  feel.  In 
length  of  staple  it  varies  from  ITJ  to  i  J  ins.,  with  a  mean  of  1.28  ins. ; 
its  mean  diameter  is  about  0.00078  in.  Most  of  the  fibres  are 
only  partially  twisted.  Smooth  Peruvian  has  a  soft,  smooth  feel, 
but  the  staple  is  not  so  strong  as  the  preceding.  The  length  is 
about  the  same  as  the  foregoing,  as  is  also  the  diameter.  Per- 
nambuco  has  a  slight  golden  color  and  feels  harsh  and  wiry.  It 
is  a  variety  of  Brazilian  cotton.  It  is  rather  regular  in  length 
of  staple,  the  mean  bring  \{  ins.  The  diameter  averages  0.00079 
in.  Under  the  microscope  the  twists  appear  regular  and  well- 
defined.  Maranhams  cotton  is  very  similar  to  the  preceding  in 
microscopic  appearance  and  length  and  diameter  of  staple. 
Ceara  is  a  Brazilian  cotton,  rather  inferior  to  the  others  by  reason 
of  its  considerable  variation  in  length  of  staple.  Mart-io  is  a 


COTTON.  121 

similar  variety,  but  somewhat  harsher.  West  Indian  cottons 
nearly  all  belong  to  the  peruvianum  species;  they  are  usually 
long  in  staple  and  harsh  and  wiry  in  feel,  and  only  of  moderate 
strength.  The  length  is  quite  uniform  and  averages  i\  ins. 
The  diameter  varies  considerably,  but  has  an  average  of  about 
0.00077  m-  The  twist  is  short  and  very  uniform,  surpassing 
even  sea- island  in  this  respect. 

Chinese  cotton,  also  known  as  Nankin  cotton,  is  classified 
as  G.  religiosum;  it  yields  a  naturally  colored  fibre,  being  rather 
dark  yellowish  brown.  It  grows  principally  in  China  and  Siam. 

3.  Vegetable  Silks. — Besides  the  cotton  derived  from  the 
Gossypium  family,  there  is  a  similar  seed-hair  fibre  obtained 
from  what  is  known  as  the  cotton-tree  or  Bombax  cotton,  or  vege- 
table down,  the  growth  of  which  is  confined  almost  exclusively 
to  tropical  countries.*  The  fibre  is  soft,  but  rather  weak  as 
compared  with  ordinary  cotton;  in  color  it  varies  from  white 
to  yellowish  brown,  and  it  is  quite  lustrous.  Physically  Bombax 
cotton  differs  from  true  cotton  in  not  possessing  any  spiral  twist 
and  showing  irregular  thickenings  of  the  cell- wall.  In  its  chemical 
constitution  it  differs  from  the  other  cotton  by  containing  a 
certain  amount  of  lignified  tissue ;  consequently  it  gives  a  yellow 
coloration  when  treated  with  anilin  sulphate  or  iodin  and  sul- 
phuric acid,  and  by  these  tests  may  be  distinguished  from  true 
cotton,  t 

*  There  are  a  number  of  varieties  of  vegetable  down,  of  which  the  following 
are  the  principal: 

Bombax  ceiba,  from  tropical  America. 

Bombax  heptaphyllum,  from  same  countries. 

Bombax  malabaricum,  from  south  Asia  and  Africa. 

Gossypium  cochlospernum,  from  India. 

Ochroma  lagopus,  from  the  West  Indies. 

Chorisia  speciosa,  from  South  America. 

Eriodendron  anfractuosum,  or  Bombax  pentandrum,  from  south  Asia. 
The  Rama  limpa  cotton  of  Brazil  is  obtained  from  Bombax  heptophyllum. 
The  product  known  in  Holland  as  kapok  is  obtained  from  B.  pentandrum.  The 
Edredon  vegetal  and  Pattes  de  lievre  of  the  French  trade  are  products  of  Ochroma 
lagopus.  The  Ouate  •vtgttal  is  a  mixture  of  Bombax,  Ochroma,  and  Chorisia 
varieties. 

f  The  microscopic  characteristics  of  vegetable  down  are  as  follows:  The 
fibre  consists  of  a  single  hair  possessing  a  conical  shape;  the  base  is  frequently 


122  THE   TEXTILE  FIBRES. 

Another  seed-hair  which  is  utilized  as  a  fibre  is  Asdepias 
cotton,  which  is  also  known  as  vegetable  silk,  as  the  fibres  possess 
a  very  high  lustre.  This  cotton,  however;  is  quite  brittle  in  nature 
and  possesses  but  little  strength;  hence  attempts  at  spinning  it 
have  not  proved  very  successful.  As  this  fibre  is  also  somewhat 
lignified,  it  may  be  distinguished  from  true  cotton  by  the  appli- 
cation of  the  above-mentioned  tests.  When  examined  under 
the  microscope  it  shows  thickened  streaks  in  the  cell- wall  which 
serve  to  distinguish  it  from  Bombax  cotton.* 

swollen  or  lace-like  in  structure.  The  length  varies  from  i  to  3  cm.  The  cross- 
section  is  circular,  so  that  the  fibres  are  not  flat  as  with  cotton.  The  contents 
of  the  inner  canal  consist  of  air  and  a  dried-up  protoplasmic  membrane.  As 
all  vegetable  downs  are  more  or  less  lignified,  their  fibres  swell  but  slightly  when 
treated  with  Schweitzer's  reagent.  The  thickness  of  the  fibres  varies  from  20 
to  50  ft. 

Hohnel  gives  the  following  description  of  the  chief  varieties  of  vegetable  down: 

1.  Bombax  ceiba;  length  i  to  1.5  cm.     B.  malabaricum  has  a  fibre-length  of  i 
to  2  cm.,  and  B.  heptaphyllum  from  2  to  3  cm.      The  last  is  by  far  the  longest 
and  strongest  variety,  and  is  sometimes  used  in  spinning.     The  diameter  of  the 
Bombax  fibres  varies  from  19  to  43  /(,  with  an  average  of  25  p. 

2.  The  hairs  of  Eriodendron  an}ractuosnm  are  very  similar  to  the  preceding, 
and  it  is  difficult  to  distinguish  between  them. 

3.  The  fibres  of  Ochroma  lagopus  are  0.5  to  1.5  cm.  in  length,  and  are  thicker 
at  the  middle  than  at  the  ends.     The  cell-wall  is  quite  thick,  and  the  fibres  are 
more  highly  lignified  than  the  foregoing. 

Pulu  fibre  can  also  be  classed  under  the  general  name  of  vegetable  down. 
It  is  the  hair  obtained  from  the  stems  of  fern-trees,  more  especially  the  Cibotium 
glaucum  (from  Sandwich  Islands).  The  fibres  are  lustrous,  of  a  golden-brown 
color,  very  soft  and  not  very  strong.  They  are  about  5  cm.  in  length,  and  are 
composed  of  a  series  of  very  flat  cells  pressed  together  in  a  ribbon-like  form.  The 
fibre  is  only  employed  as  a  stuffing  material  and  is  never  woven. 

*  There  are  several  varieties  of  vegetable  silks,  chief  among  which  are  the 
following:  Asdepias  curassavica,  from  the  West  Indies;  Calotropis  gigantea, 
from  south  Asia  and  Africa;  Afarsdcnia,  from  India;  Beaumontia  grandi florid, 
from  India;  Strophnnttts,  from  Senegal.  True  vegetable  silks  as  a  rule  may  be 
recognized  as  follows:  They  are  4  to  6  cm.  in  length;  possess  a  silky  lustre;  in 
color  are  white  to  yellow  or  reddish  yellow;  and  are  stiff.  Their  thickness  is 
sometimes  as  much  as  80  fj.,  but  more  generally  35  to  60  fj..  The  fibre  is  rela- 
tively thin-walled,  but  shows  frequently  on  the  inside  several  thickened  longi- 
tudinal ridges,  whi(  h  ;irr  sometimes  very  apparent  and  at  others  scarcely  notice- 
able. The  ridges  are  semicircular  in  cross-section,  though  sometimes  flat  and 
linnd.  The  ridges  give  the  «  rll-wull  the  appearance  of  being  uneven  in  thick- 
The  ridges  form  the  chief  microscopical  feature  of  vegetable  silk,  and 
serve  to  distinguish  these  fibres  from  vegetable  downs,  which  are  otherwise  very 
similar.  The  cross-section  of  the  fibre  is  circular,  and  the  cell-wall  is  lignified. 


COTTON.  123 

Cotton-silk  is  a  seed-fibre  which  appears  to  be  more  or  less 
identical  with  the  foregoing.  It  is  derived  from  an  Indian  plant 
botanically  classified  as  Salmalia,  a  genus  of  Malvacea]  the 
plant  is  a  rather  large  tree,  attaining  the  height  of  70  to  80  ft. 
Although  the  fibre  is  very  beautiful  in  appearance,  having  the 
texture  and  lustre  of  silk,  it  is  not  suitable  for  purposes  of  spinning, 
as  its  tensile  strength  is  quite  low.  Under  the  microscope  the 
fibres  appear  as  thin,  smooth,  transparent  tubes  without  the 
longitudinal  markings  of  the  silk  fibre,  and  differing  from  cotton 
in  not  showing  the  twists  and  irregularities  of  that  fibre,  and 
in  not  being  flattened  but  cylindrical  in  appearance.  Cotton- 
silk  may  be  readily  distinguished  from  silk  by  igniting  a  fibre 
in  a  flame,  when  the  former  will  burn  with  great  rapidity,  whereas 
silk  will  fuse  and  give  off  the  characteristic  odor  of  a  burning 
animal  fibre.  Cotton-silk  is  evidently  a  form  of  cellulose  fibre; 
its  silky  appearance  being  due  to  the  delicacy  and  thinness  of 
the  cell-walls  and  their  smooth  surface.  It  is  very  sensitive  to 
the  action  of  dilute  acids;  towards  dyestuffs  it  behaves  like 
cotton,  not  combining  with  the  basic  colors  except  after  a  pre- 
vious mordanting.  There  are  several  other  plants  which  yield 
seed- hairs,  which,  as  a  rule,  are  not  of  much  value  for  purposes 
of  spinning  and  weaving;  but  they JincL_Jcajther  extensive  use 
for  upholstery  purposes  and  twines.  As  a  rule,  these  fibres  are 
colored  red  by  phlcrrdgluconand  hydrochloric  acid,  and  yellow 
with  aniline  sulphate,  showing  the  presence  of  lignified  tissue. 
Usually  the  fibres  are  somewhat  yellow  in  color  and  possess 
considerable  lustre. 


CHAPTER  X. 

THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON. 

i.  Physical  Structure. — Physically  the  individual  cotton  fibre 
i  consists  of  a  single  long  cell,  with  one  end  attached  directly  to  the 
surface  of  the  seed.  While  growing,  the  fibre  is  round  and  cylin- 
drical, having  a  central  canal  running  through  it;  but  after  the 
enclosing  pod  has  burst,  the  cells  collapse  and  form  a  flat  ribbon- 
like  fibre,  which  shows  somewhat  thickened  edges  under  the 
microscope.  The  juices  in  the  inner  tube,  on  the  ripening  of  the 
fibre,  are  drawn  back  into  the  plant,  or  dry  up,  and  in  doing  so 
cause  the  fibre  to  become  twisted  into  the  form  of  an  irregular 
spiral  or  screw-like  band.*  Fibres  that  have  not  ripened  differ 
somewhat  in  these  characteristics,  being  straight  and  having  the 
inner  canal  stopped  up,  in  consequence  of  which  they  do  not  spin 
well  and  are  difficult  to  dye,  showing  up  as  white  specks  in  the 
finished  goods;  this  is  known  as  dead  cotton.  The  presence  of  an 
inner  canal  in  the  cotton  fibre  no  doubt  adds  to  its  absorptive 
power  for  liquids,  and  its  capillary  actiori  allows  cotton  to  retain 
salts,  dyestuffs,  etc.,  with  considerable  power;  but  too  much  im- 
portance in  this  respect  must  not  be  attributed  to  the  canal,  for 
when  cotton  is  mercerized  the  canal  is  almost  entirely  obliterated 
by  the  walls  being  squeezed  together,  and  yet  mercerized  cotton 
is  much  more  absorptive  of  dyes,  etc.,  than  ordinary  cotton. 
The  capillarity  of  the  cotton  fibre  is  no  doubt  principally  due  to 
the  existence  of  minute  pores  which  run  from  the  surface  inward. 
The  crystallization  of  salts  in  these  pores  and  in  the  central  canal 
may  lead  to  the  rupturing  of  the  fibre,  as,  for  instance,  when 
filter- paper  is  made  by  disintegrating  cotton  fibres  by  saturating 
them  with  water  and  then  freezing  them. 

The  cotton  fibre  is  rather  even  in  its  diameter  for  the  gR-ntrr 

*  The  number  of  twists  in  the  cotton  fibre  in  the  raw  state  is  said  to  be  from 
300  to  500  per  inch. 

124 


THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON.   125 


part  of  its  length,  though  it  gradually  tapers  to  a  point  at  its  out- 
growing end.  The  different  varieties  of  cotton  show  consider- 
able variation,  both  in  length  and  diameter  of  fibre;  in  sea- island 
cotton  the  length  is  nearly  2  ins.,  while  in  Indian  varieties  it  is 
often  less  than  i  in.  The  diameter  varies  from  0.00046  to  o.ooi 
in. ;  the  longest  fibres  having  the  least  diameter. 

The  following  table  of  the  length  and  diameter  of  different 
varieties  of  cotton  fibres  has  been  collated  as  a  mean  of  several 
observers : 


Name  of  Cotton. 

Length 
in  mm. 

Diameter 
in  /i. 

Name  of  Cotton. 

Length 
in  mm. 

Diameter 
in  ft. 

Sca-isldnd 

41  .q 

9.6s 

West  Indian  

32.  3 

19.6 

4.6  6 

American  

2O  0 

Orleans 

07    o 

IO    2 

John  Isle 

7Q      ? 

Upland  

20  .  < 

10   4 

jc    7 

16  18 

Texas 

24.    3 

16  6 

Fitschi 

48.7 

16.7 

Mobile  

2S  .O 

IQ-4 

Tahiti         

42.O 

16.3 

Georgia  

2^.4 

10.  3 

7.8  o 

1C      7 

Mississippi  

24    2 

34 

Egyptian 

•?2     I 

o-o 
16  7 

Louisiana  

2C  .O 

Gallini 

•27    2 

17    I 

Tennessee  

2Z  .  I 

IZ.O 

74      A 

18  7 

A.  jrican 

27    6 

20  8 

White 

34-4 

3i  8 

IO    ^ 

Indian 

IO    3 

Smyrna  

28.? 

22.8 

Hingunghat  

28.3 

2O.  O 

18  8 

Dhollerah  

28   2 

21     C 

"\Iaranham 

28  8 

2O   4 

Broach  

2O  O 

21    8 

Pernambuco 

3C      2 

2O   O 

Tinnevelly  

23    O 

21  .O 

Surinam  
Paraiba  
Ceara  

30.2 
29.7 
28.1 

20.  o 

Oharwar  
Oomrawuttee.  .  .  . 
Comptah  

23.6 
24.1 
23.8 

21.0 

21-5 
21.  Z 

Maceo 

2Q    3 

Madras  

21    8 

21    8 

Peruvian  rough 

2O    O 

21    5 

Scinde  

2O   4 

21     3 

Smooth 

•2Q    O 

^i  .^j 
21  .  5 

Bengal  

2S.  7 

23.  7 

37    < 

Chinese 

21    4 

24    I 

O/  -D 

Evan  Leigh  (Science  of  Modern  Cotton  Spinning)  gives  the 
following  summary  of  the  length  and  diameter  of  cotton  fibres: 


Place  of  Growth. 

Kind  of  Cotton. 

Length  in  Ins. 

Diameter  in  Ins. 

Min. 

Max. 

Mean. 

Min. 

Max. 

Mean. 

United  States  .  . 
Sea-islands  .... 
South  America. 
Eevpt.  . 

New  Orleans.  .  . 
Long  stapled.  .  . 
Brazilian.  .  .  . 

0.88 
1.41 
1.03 
1.30 
0.77 
°-95 
i-36 

.16 

.80 
•31 
-  -52 

.02 
.21 
•65 

.02 
.61 

-17 
.41 
0.89 
.08 

•5° 

.000580 
.000460 
.000620 
.  000590 
.000649 
.000654 
.000596 

.000970 
.000820 
.000960 
.000720 
.000040 
.000996 
.000864 

.000775 
.  000640 
.000790 
.000655 
.000844 
.000825 
.000730 

Egyptian.  . 

India  -! 

Native  
American  seed  .  . 
Sea-island  seed  . 

126 


THE   TEXTILE  FIBRES. 


Hannan  gives  the  following  varieties  and  qualities  of  cotton 
to  be  met  with  in  commerce: 


Types. 

Variety. 

fs 

Diameter, 
Ins. 

Counts. 

Use. 

Properties. 

Sea-island  .  . 
Egyptian.  .  . 

Peruvian.  .  . 
Brazilian.  .  . 

American.  .  . 

Edisto  

2.  2O 
1.85 

i-75 

i.  80 
1.50 
i.  60 
1.50 
I-2S 

I.  00 

1.25 

I.OO 

1.25 
1.50 

!-I5 

i.iS 

1.20 

1-IS 

I.  2O 
I.30 

.00063 

.00063 
.00063 

.00063 
.00070 

.00066 
« 

.00078 

.00078 
«< 

.00079 
« 

« 
« 
« 

.00084 
« 

300-400 

150-300 
100-250 

« 

i  2O-down 
25o-down 
2oo-down 

IOO 

70 

50-70 
« 

40-50 

50-70 
50-60 
60 

50-60 
40-50 
40-60 
50-60 

40-50 
34-46 
32-40 

50-60 

Warp 
or  weft 

do. 
do. 

do. 
do. 
Warp 
Weft 

Warp 
or  weft 
do. 

Warp 
Weft 
Warp 

Warp 
do. 
Weft 

Warp 
or  weft 
Weft 

Warp 
or  weft 
Weft 

Warp 
or  weft 
Warp 
or  weft 
do. 

Warp 

Long,     fine     silky, 
and     of     uniform 
diameter 
Shorter,  but  similar 
to  above 
Less      uniform      in 
length,    but    silky 
and  cohesive 
Good,      fine,      and 
glossy  staple 
Long,  strong,  high- 
ly endochromatic 
High  class  staple  of 
good  strength 
Of  good  staple  and 
lustre 
Fairly  good  staple 

Pearly  white,   good 
long  staple 
Strong,  wooly,  and 
harsh  staple 
Less     wooly,     and 
softer  staple 
Color    weaker    and 
harsher     than 
brown  Egyptian 
Strong  and     wiry 
Harsh  and  wiry 
Good,    white,    and 
cohesive  staple 
Fairly  strong,  harsh, 
of  good  color 
Soft,     white,    and 
harsh  staple 
Soft,     pliable,    and 
good  for  hosiery 
Exotic  from  Ameri- 
can    seed,     white 
and  silky  staple 
Fairly    strong,    but 
harsh  and  wiry 
Medium   length, 
pearly,  white 
Similar     to     above, 
rather  harsher  and 
more  glossy 
Good,   white,   long; 
blends  with  brown 
Egyptian 

Florida 

Fiii  . 

Tahiti 

Brown 

Gallini  
Menouffieh.  .. 
Mitafiffi. 

White  

Rough  
Smooth  
Red  

Pernams  
Maranhams.  . 
Ceara 

Paraiba  . 

Rio  Grande.  . 
Maceio 

Santos  
Bahia. 

Orleans.  . 

I.I 

1.05 

1.20 

.00077 
« 

Texas 

Allanseed.  .  .  . 

THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON.    127 


Types. 

Variety. 

!i 
j 

Diameter, 
Ins. 

Counts. 

Use. 

Properties. 

A.  merican 

Mobile 

i  .00 

00076 

4.0—^0 

Warp 

Even-running     sta- 

Norfolks   
St  Louis 

I.OO 

o  .  oo 

el 

tt 

40-50 

7O—  32 

or  weft 
Weft 
Warp 

ple,  soft  and  cohe- 
sive 
Used    for    Oldham 
counts  of  50*5 
Staple  irregular 

Ronoaks  
Boweds  

0.90 

ti 

30-34 

36 

do. 
Weft 

glossy,  but  short 
A  white  and  strong 
staple 
Similar  to  uplands 

Benders 

I     IO 

OOO77 

60 

Warp 

Strong     creamy    or 

Memphis.  .  .  . 
Peeler^ 

I.OO 
I     2^ 

« 
n 

40-50 
60-80 

do. 
Weft 

white,  for  Turkey- 
red  dyes 
Bluish  white,  for  ex- 
tra hard  twists 
Long  silkv  fine  sta- 

Uplands .  . 

I  .  OO 

tt 

36—4.0 

do. 

ple;     adapted   foi 
velvets,  etc. 
Glossy  when  clean, 

Alabama  

o.oo 

tt 

26—30 

Warp 

apt    to    be    dullT 
sandy,  and  leafy 
Short  staple,  of  less 

Linters  

8—  10 

or  weft 
Weft 

strength,     varying 
color 
Short    stapled    gin 

Greek  

Tennessee  
Smyrna. 

0.90 

I.2<) 

tt 

28 
7,6—4.0 

Warp 
or  weft 
Warp 

waste 
Of    varying    length 
and  color 
Harsh   and   strong, 

African.  .  .  . 
West  Indian 

Lagos  
C  arthagena 

0.80 

I    ^O 



20-26 
26 

Weft 
Warp 

adapted  for  double 
yarns. 
Dull  and  oil-stained  ; 
irregular  in  length 
and  strength 
From  exotic  seeds  \ 

La  Guayran  . 

1  .  20 

AQ 

Warp 

fairly  strong 
Irregular  and  short, 

China  

China  

•JQ 

or  weft 
Weft 

but  silky  staple 
Harsh,    short,    and 

Australian  . 
East  Indian 

Queensland.  . 
Oomrawuttee 
Hingunghat.  . 
Comptah  .  .  . 

J-75 

I  .00 
I.OO 

T    or 

.00066 

.00083 
tt 

1  2O-2OO 
20-32 
28-36 

Warp 
or  weft 
Warp 

Weft 
Warp 

white 
Long,   white,  silky, 
fine  diameter 
Short,    strong,    and 
white 
Best    white    Indian 
staple 
Generally  dull,  and 

Broach  

Dharwar  

I 

0.90 

I.OO 



28-36 

28 

or  weft 
Weft 

Warp 

charged  with  leaf 
Like     Hingunghat, 
gives    good    white 
weft 
Exotic  from  Ameri- 
can seeds 

128 


THE    TEXTILE  FIBRES. 


Types. 

Variety. 

£* 
c£ 
3 

Diameter, 
Ins 

Counts. 

Use. 

Properties. 

East  Indian. 

Assam  

0.50 



15-20 

Warp 

White,    but    harsh. 

To      blend      with 

other  cottons 

Bengals  

0.80 



20-30 

Warp 

Dull   and  generally 

or  weft 

charged  with  leaf 

Bilatee  

0.50 



10-20 

do. 

Weak,  brittle,     and 

coarse 

Dhollerah.  .  .  . 

0.70 

15-20 

do. 

Strong,  dull,  and  co- 

hesive 

Surat  

0.60 

10-15 

do. 

Dull  and  leafy,  often 

stained 

Scinde  

0.50 



to  10 

do. 

Very    strong,    dull, 

short,     and     poor 

staple 

Tinnevelly.  .  . 

0.80 

24-30 

do. 

Lustrous  white,  soft, 

and    adapted    for 

hosiery 

Bhownuggar 

i  .00 

28-30 

Warp 

White   when  clean; 

**     O 

often     leafy     and 

dirty 

Cocoanada.  .  . 

0.70 



10-14 

Brown 

Brown     and     dull; 

weft 

used      as     quasi- 

Egyptian 

Bourbon 

I    OO 

30 

Weft 

Exotic  ',  of  good  sta- 

ow 

ple;  scarce 

Khandeish.  .  . 

0.80 

.00083 

20-26 

Warp 

Similar   in   class   to 

or  weft 

Bengal 

Madras       o  r 

O   7O 

i  <\—  20 

do. 

Used  for  low  varns 

Westerns 

w.  i  \j 

*  j 

in  coarse  towelling, 

etc. 

Rangoon  

0.60 

to  10 

Warp 

Weak,    dull,    often 

or  weft 

stained  and  leafy 

Kurrachee.  .  . 

0.90 



28 

do. 

Fairly  strong,   dull,. 

and  leafy 

Italian  

Calabria  

0.90 



26-28 

do. 

Fairly  strong,  irreg- 

ular and  dull,  leafy 

Turkey  

Levant  

I  .  2C 

OOO77 

•26—4.0 

Warp 

Harsh,   strong,   and 

.  \-*w  i  i 

yj—i+\j 

white 

Hohncl  gives  the  following  table  for  the  thickness  of  different 
varieties  of  cotton : 


North  American:  1000 

Sea-island 14 

Louisiana  and  Alabama 17 

Florida 18 

Upland  and  Tennessee 19 

Southern  and  Central  American 15-21 

Average 19 


THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON.    129 


East  Indian:  I000 

Dollerah  and  Bengal 20 

Madras 28 

Chinese: 

Nankin 25-40 

Egyptian: 

Macco 15 

Levianthan 24 

European: 

Spanish 17 

Italian 19 

According  to  Wiesner  the  thickest  part  of  the  cotton  fibre  is 
not  directly  at  the  base,  but  more  or  less  towards  the  middle. 
He  gives  the  following  measurements  of  thickness  at  different 
parts  of  the  fibre: 


G.  arbor  e-um, 

G.  acuminatum, 

G.  herbaceutn, 

Position. 

25  mm.  long. 

28  mm.  long. 

25  mm.  long. 

mm. 

mm. 

mm. 

IOOO 

IOOO 

IOOO 

Point 

0 

0 

0 

i 

8.4 

4.2 

4.2 

2 

21 

21.6 

5-8 

3 

29 

16.8 

10.  0 

4 

25 

29-4 

16.8 

5 

29 

17.0 

21.0 

6 

25 

21.  I 

16.9 

7 

21 

21.  I 

21.0 

Base 

J7 

21.  O 

16.8 

Mean 

19-5 

16.9 

12.5 

The  length  of  the  cotton  fibres  attached  to  a  single  seed  is  by 
no  means  constant.  The  longest  fibres  usually  appear  at  the 
crown  of  the  seed,  while  the  shortest  occur  at  the  base.  There 
is  also  frequently  an  undergrowth  of  very  short  fuzzy  fibres.  In 
ginning,  the  very  short  fibres  are  ordinarily  not  removed  from 
the  seed,  but  always  more  or  less  do  come  in  with  the  ginned 
cotton.  These  short  fibres  are  termed  "neps,"  and  their  pres- 
ence in  any  considerable  amount  materially  affects  the  commercial 
value  of  the  cotton.  This  short  undergrowth  of  neps  appears  to 
be  made  up  of  incompletely  developed  or  immature  fibres,  though 
neps  may  also  arise  through  excessive  breaking  of  fibres  by  im- 
Derfect  manipulation  in  the  carding  and  spinning  processes. 


I3o 


THE    TEXTILE  FIBRES. 


Bowman  (Structure  of  the  Cotton  Fibre)  gives  the  following 
table  showing  the  extreme  variation  in  the  length  and  diameter 
of  different  kinds  of  cotton: 


Cotton. 

Variation  in 
Length. 

Variation  in 
Diameter. 

American  (Orleans) 

o  28  in. 

o  000300  in 

Sea-island 

O    30     " 

o  000360    " 

Brazilian 

"•OV 

o  28 

o  000340    " 

EtrvDtian 

O    22     " 

o  000130    " 

Indian  (Surat)    

0.2?      " 

0.000301    " 

Bowman  calls  attention  to  the  fact  that  Egyptian  cotton  is  the 
most  regular  in  both  length  and  diameter;  while  sea- island  cot- 
ton, though  possessing  the  greatest  length  and  fineness  of  staple, 
also  exhibits  the  greatest  variation.  It  is  also  noticeable  that  the 
variation  in  the  diameter  is  proportionately  very  much  larger 
than  the  variation  in  the  length.  Bowman  also  gives  an  inter- 
esting comparison  of  the  size  of  the  individual  cotton  fibre  with 
objects  of  common  experience.  If  a  single  fibre  of  American 
cotton  were  magnified  until  it  becomes  i  in.  in  diameter,  it  would 
be  a  little  over  100  ft.  long,  while  a  sea-island  fibre  of  the  same 
diameter  would  be  about  130  ft.  It  requires  from  14,000  to 
20,000  individual  fibres  of  American  cotton  to  weigh  i  grain,  hence 
there  are  about  140,000,000  in  each  pound,  and  each  fibre  weighs 
on  an  average  only  about  0.00006  gr.  If  the  separate  fibres  con- 
tained in  one  pound  were  placed  end  to  end  in  a  straight  line, 
they  would  reach  2200  miles. 

Hohnel  gives  the  following  table  of  the  different  varieties  of 
cotton  arranged  according  to  their  length  of  staple : 


Gossypium  barbadense 


viti folium 

conglomeration 

acuminatum 

arboreum 

herbaceunt 


(Sea-island) 4.05  cm. 

(Brazilian) 4.00  " 

(Egyptian) 3.89  " 

(Pernambuco) 3 . 59  " 

(Martinicjue) 3.51  " 

(Indian) 2.84  " 

(Indian) 2.50  " 

(Macedonian) i  .82  " 

(Bengal) i .  03  " 


THE  PHYSICAL  STRUCTURE  4ND  PROPERTIES  OF  COTTON.   131 

From  its  behavior  with  a  solution  of  ammonio-copper  oxide, 
the  cotton  fibre  appears  to  consist  of  four  distinct  parts  struc- 
turally. When  treated  with  this  solution  and  examined  under 
the  microscope,  the  fibre  is  seen  to  swell,  but  not  uniformly;  it 
seems  that  at  regular  intervals  there  are  annular  sections  which 
do  not  swell*  The  result  is  that  the  fibre  assumes  the  form  of  a 
distended  tube  tied  at  intervals  somewhat  after  the  manner  of  a 
string  of  sausages.  Soon  the  main  portion  of  the  fibre  begins  to 
dissolve,  whereupon  the  walls  of  the  central  canal  are  seen  quite 
prominently;  the  dissolving  action  proceeds  rapidly,  but  appar- 
ently there  is  a  thin  cuticular  tissue  surrounding  the  fibre  which 
resists  the  action  of  the  solvent  for  a  much  longer  time  than  the 
inner  portion.  The  walls  of  the  central  canal  also  resist  the 
action  of  the  liquid  to  even  a  greater  extent  than  the  external 
tissue;  the  annular  contracted  ligatures  in  the  fibre  also  persist 
after  the  rest  of  the  fibre  has  dissolved.  Thus  we  have  four 
structural  parts  made  evident  (see  Fig.  37) : 

(a)  The  main  cell-wall,  probably  composed  of  pure  cellulose, 
and  rapidly  and  completely  soluble  in  the  reagent. 

(b)  An  external  cuticular  fibre,  probably  of  modified  cellulose, 
and  more  resistant  to  the  action  of  the  reagent. 

(c)  The  wall  of  the  central  canal,  which  resists  the  solvent 
power  of  the  reagent  even  more  than  the  cuticle. 

(d)  The  annular  ligatures  surrounding  the  fibre  at  intervals, 
which  persist  even  after  the  canal- walls  have  dissolved. 

O'Neill  (in  1863)  nrs^  pointed  out  this  complex  structure  of 
the  cotton  fibre.  He  says:  "I  believed  that  in  cotton-hairs  I 
could  discern  four  different  parts.  First,  the  outside  membrane, 

*  Hohnel  considers  these  ligatures  as  merely  parts  of  the  cuticle;  he  explains 
their  formation  by  the  fibre  swelling  so  considerably  as  to  rupture  the  undisturbed 
cuticle,  which  in  places  adheres  to  the  fibre  in  the  form  of  irregular  shreds  which 
are  visible  only  with  difficulty.  In  other  places  where  the  rupture  occurs  obliquely 
to  the  length  of  the  fibre,  the  cuticle  becomes  drawn  together  in  annular  bands 
surrounding  the  fibre,  while  between  these  rings  the  much-distended  cellulose 
protrudes  in  the  form  of  globules.  The  inner  membrane  or  canal  which  persists 
after  the  rest  of  the  fibre  has  dissolved  is  an  exceedingly  thin  tissue  of  dried  proto- 
plasm which  was  contained  in  the  living  fibre.  On  bleached  cotton  the  cuticle 
may  be  almost  entirely  lacking,  and  hence  such  fibres  will  not  exhibit  the  charac- 
teristic appearance  above  mentioned. 


132  THE    TEXTILE  KBRES. 

which  did  not  dissolve  in  the  copper  solution.  Second,  the  real 
cellulose  beneath,  which  dissolved,  first  swelling  out  enormously 
and  dilating  the  outside  membrane.  Thirdly,  spiral  fibres, 
apparently  situated  in  or  close  to  the  outside  membrane,  not 
readily  soluble  in  the  copper  liquid.  These  were  not  so  elastic 
as  the  outside  membrane  and  acted  as  strictures  upon  it,  pro- 
ducing bead-like  swellings  of  a  most  interesting  appearance;  and 
fourthly,  an  insoluble  matter,  occupying  the  core  of  the  cotton- 
hair,  and  which  resembled  very  much  the  shrivelled  integument  in 
the  interior  of  quills  prepared  for  making  pens."  He  also  notes 
that  the  insoluble  outside  membrane  was  not  evident  on  bleached 
cotton,  hence  concluding  that  either  it  had  been  dissolved  away, 
or  some  protecting  resinous  varnish  had  been  removed,  and 
then  it  became  soluble.  He  also  obtained  the  same  general 
results  by  treatment  with  sulphuric  acid  and  chloride  of  zinc  in 
place  of  the  ammonio- copper  solution. 

According  to  Butterworth,  who  observed  the  cotton  fibre 
treated  with  the  ammonio-copper  solution  under  a  magnification 
of  1600  diameters,  there  are  spiral  threads  apparently  crossing 
and  tightly  bound  round  the  fibre  at  irregular  distances,  also 
spiral  threads  passing  from  one  stricture  to  another;  the  core  of 
the  fibre  has  a  spiral  form,  and  in  cross-section  shows  the  presence 
of  concentric  rings  (see  Figs.  35  and  36). 

There  appears  to  be  some  difference  in  the  action  of  ammonio- 
copper  solution  on  fibres  of  different  physiological  structure. 
Immature  or  unripe  fibres  dissolve  readily  without  exhibiting 
any  structural  differences.  The  tubular-shaped  fibres  swell  out 
as  a  whole  and  finally  dissolve  without  showing  any  structural 
modifications,  except  that  in  many  cases  an  inner  core  is  left. 

Examination  with  the  highest  microscopic  powers  has  not 
shown  any  cellular  structure  pertaining  to  the  cellulosic  contents 
of  the  cotton  fibre;  it  is  probably  composed  of  fine  layers  super- 
imposed one  upon  the  other. 

2.  Microscopical  Properties. — The  microscopical  characteris- 
tics of  the  cotton  fibre  are  so  pronounced  as  to  readily  differentiate 
it  from  all  others.  As  already  noted,  it  presents  the  appearance 
of  a  flat,  ribbon-like  band  more  or  less  twisted  on  its  longitudinal 


THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  CO!  TON.    133 

axis  (see  Fig.  33).     The  cell-wall  is  rather  thin  and  the  lumen 
occupies  about  two-thirds  of  the  entire  breadth  and  shows  up 


FIG.  33. — Unripe  Cotton  Fibres  (X35o). 
Showing  a  flat,  ribbon-like  form  and  thin  and  almost  transparent  appearance. 

very  prominently  in  polarized  light.  Between  its  thickened 
edges  the  fibre  exhibits  the  appearance  of  a  finely  granulated 
surface.  Fibres  of  dead  cotton,  or  those  which  have  not  reached 
their  full  maturity,  are  seldom  twisted  spirally  and  do  not  have 
a  lumen,  but  are  thin,  transparent  bands  (see  Fig.  34). 

Microscopically  cotton  fibres  differ  considerably  among  them- 
selves, but  in  general  may  be  divided  into  four  classes : 

(a)  Fibres    exhibiting    a    smooth,    straight,    flat    appearance 
with  no  suggestion  of  internal  structure.     This  includes  immature 
cotton   fibres    and  also  fibres  which  have  overripened  by  not 
being  picked  until  some  time  after  attaining  full  maturity.     The 
external  wall  of  the  fibre  is  very  thin. 

(b)  Fibres    exhibiting    a    normal    appearance    through    some 
portions    of  their   length,    and    in   other    parts   a   structureless 
appearance  as  in  (a).     This  may  be   termed  "kempy"  fibre;  the 
solid,  tubular  portion    of    the  fibre  is  particularly  resistant  to 
the  absorption  of  liquids  and  dyestuffs,  and  consequently  remains 
uncolored  while  the  rest  of  the  fibre  is  dyed. 

(c)  Straight,  tubular  fibres  exhibiting  a  well-defined  internal 
structure  and  a  transparent  cell- wall  of  van-ing  thickness. 


134  THE   TEXTILE  FIBRES. 

(d)  Normal  structure  of  twisted,  band-like  form. 

In  cross-section  the  immature  fibres  show  only  a  single  line 
with  no  structure,  and  but  little  or  no  indication  of  an  internal 
opening.  The  mature  fibre  is  thicker  in  cross-section  and  exhibits 
a  central  opening. 

The  most  characteristic  of  the  microchemical  reactions 
for  cotton  is  that  with  ammoniacal  copper  solution,  already 
described.  With  bleached  cotton  the  external  cuticle  may  be 
absent,  and  hence  such  a  fibre  may  not  show  any  distension. 


FIG.  34. — Root  of  Cotton  Fibre  (X35o). 

Showing  the  irregular  fracture  caused  by  the  fibre  being  torn  from  the  seed;  at 
the  broad,  flat  portion  of  the  base  of  the  fibre  may  also  be  seen  the  longitudinal 
wrinkles  and  the  cross-fractures  of  the  cuticle. 

With  iodin  and  sulphuric  acid  the  cotton  fibre  becomes  blue 
in  color,  though  the  cuticle  remains  colorless.  Tincture  of 
madder  gives  an  orange  color;  fuchsin  produces  a  red  color 
which  is  destroyed  by  the  addition  of  ammonia.  Flax  does 
not  show  this  latter  reaction,  hence  this  serves  as  a  chemical  means 
of  distinguishing  between  cotton  and  linen.  Anhydrous  stannic 
chloride  gives  a  black  color,  and  sulphuric  acid  dissolves  the 
cotton  fibre  rapidly. 

3.  Physical  Properties. — The  natural,  spiral-like  twist  present 
in  the  cotton  fibre  causes  the  latter  to  be  especially  adaptable  to 
purposes  of  spinning.  The  spinning  qualities  of  the  cotton 


THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON.    135 

fibre,  however,  depend  not  only  on  the  nature  and  amount  of  L 
twist  which  causes  the  individual  fibres  to  lock  themselves  firmly 


FIG.  35. — Cotton  Fibre,  Swollen  with  Schweitzer's  Reagent 
Showing  the  walls  of  the  internal  canal,  and  the  spirally  fibrous  structure  of  the 

cellulose  wall. 

together,  but  also  on  the  length  and  fineness  of  staple.     These 
three  qualities  in  general  will  designate  the  character  and  fineness 


FlG.  36. — Portion  of  Fig.  35  very  highly  magnified  (X2OOO). 
The  structure  of  the  cellulose  is  here  plainly  apparent. 


of  yarn  which  may  be  spun  from  any  sample  of  cotton.     Sea- 
island  cotton  lends  itself  to  the  spinning  of  very  fine  yarns,  being 


136  THE   TEXTILE  FIBRES. 

spun  to  even  300 's  (that  is,  300  hanks  of  840  yds.  each  would 
weigh  i  lb.),  and  in  an  experimental  manner  this  cotton  has 
even  been  spun  as  fine  as  2000 's. 

\/  In  its  tensile  strength  cotton  stands  between  silk  and  wool; 
whereas,  in  elasticity,  it  is-  considerably  below  either  of  the  other 
two  fibres.  The  breaking  strain  of  cotton  will  vary  from  2.5 
to  10  grams,  depending  on  the  fineness  of  staple;  the  finer  the 
fibre,  the  less  will  be  its  breaking  strain. 

Cotton  is  less  hygroscopic  than  either  wool  or  silk;  under 
normal  conditions  it  will  contain  from  7  to  8  per  cent,  of  hygro- 
scopic moisture,  though  in  a  very  moist  atmosphere  this  may  be 
considerably  increased. 

The  hygroscopic  quality  of  cotton  (and,  in  fact,  other  vegetable 
fibres  as  well)  has  much  to  do  with  its  proper  condition  during 


Pro.  37.— Appearance  of  Cotton  Fibre  on  Treatment  with  Schweitzer's  Reagent. 

(Witt.) 

a,  transverse  ligatures  of  disrupted  cuticle;  b,  irregular  shreds  of  cuticle  torn  apart; 
c,  swollen  mass  of  cellulose;  d,  walls  of  internal  canal. 

the  various  processes  of  spinning  and  finishing.     It  also  has  an 
influence  on  the  commercial  valuation  of  the  raw  material,  as 


THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON.    137 


the  amount  of  hygroscopic  moisture  varies  with  atmospheric 
conditions,  and  it  is  important  to  have  a  normal  standard  of 
reference  (see  wool  conditioning).  Its  influence  on  spinning 
is 'even  greater,  and  proper  conditions  of  atmospheric  moisture 
must  be  maintained  in  the  spinning-room  in  order  to  achieve 
the  best  results;  the  spinning  properties  of  raw  cotton,  however, 
are  also  affected  by  other  substances  associated  with  the  cellulose 
of  the  fibre,  but  it  is  without  question  that  the  physical  condi- 
tion of  cotton  is  largely  influenced  by  its  content  of  hygroscopic 
moisture,  and  this  should  be  delicately  adjusted  by  the  spinner 
to  meet  the  conditions  of  his  work.  The  mechanical  treatment 
of  woven  textile  materials  in  finishing  processes,  such  as  mangling, 
beetling,  calendering,  etc.,  is  also  dependent  for  good  results  to 
quite  an  extent  on  the  hygroscopic  condition  of  the  fibre;  the 
amount  of  moisture  present  during  the  finishing  operations, 
together  with  the  method  and  degree  of  drying,  should  be  care- 
fully studied.* 

The   following   table   shows   the   results   of   experiments   on 
the  tensile  strength  of  different  varieties  of  cotton: 


Cotton. 

Mean  Breaking  Strain. 

Grains. 

Grams. 

Sea.  -island  (Edisto)  

83-9    * 
147.6 
127.2 
107.  1 
100.6 
140.2 

147-7 
104.5. 
141.9 
163-7 

5-45 
9-59 
7.26 
6.96 

6-53 
9.11 
9.61 

6-79  , 
9.22 
10.64 

EBVDtian 

Maranham                        . 

Bengal 

Pernambuco  

New  Orleans  

Upland   .  .          

Surat  (Dhollerah)  

Surat  (Comptah) 

*  In  testing  the  influence  of  moisture  on  the  strength  of  cotton  material,  the 
Industrial  Society  at  Mulhause  reports  as  follows: 

Normal  strength  of  cloth 100 

Saturated  with  moisture 104 

Dried  on  hot  cylinder 86 

Again  dampened 103 

It  would  appear  from  these  results  that  the  alternate  moistening  and  hot  drying 
of  cotton  caused  little  or  no  deterioration  in  its  strength. 


138 


THE   TEXTILE  FIBRES. 


The  full  tensile  strength  of  the  individual  fibre,  however,  is 
not  utilized  in  the  spun  yarn.  Single  yarns  will  give  only  about 
20  per  cent.,  or  one-fifth,  of  the  breaking  strain  calculated  from 
the  strength  of  the  separate  fibres;  two-ply  yarns  give  about 
25  per  cent. 

The  following  table  exhibits  the  comparative  values  of  the 
tensile  strength  of  different  fibres.  The  " breaking  length" 
refers  to  a  length  of  thread  which  will  break  by  reason  of  its  own 
weight. 


Fibre. 

Breaking  Length 
in  Kilometers. 

Tensile  Strength, 
Kilograms  per 
Square  mm. 

Cotton 

2?    O 

37   6 

Wool          .            

8  3 

IO    O 

Raw  silk  

72     O 

44  8 

Flax  fibres  

24.O 

?c  .  2 

Jute 

2O    O 

28    7 

China  grass 

20  o 

0.    / 

Hemp 

3O    O 

4^    O 

Manila  hemp 

31  8 

Cocoanut  fibre  

JJ.   .U 

17   8 

20    2 

Vegetable  silk  

24    ? 

When  cotton  is  purified  from  its  adhering  waxy  and  fatty 
matters,  it  becomes  remarkably  absorbent.  This  quality  is 
explained  on  the  supposition  that  the  ripe  cotton  fibre  is  made 
up  of  a  series  of  tissues  of  cellulose,  separated  from  each  other 
by  intercellular  matter,  in  this  way  forming  a  series  of  capillary 
surfaces  which  are  capable  of  exerting  considerable  capillary 
force  upon  any  liquid  in  which  the  fibre  may  be  immersed.  Dry 
cotton  also  appears  to  be  remarkably  absorptive  of  gases;  it  is 
said  that  the  fibrfcan  absorb  115  times  its  volume  of  ammonia  at 
the  ordinary  atmospheric  pressure. 


CHAPTER  XI. 

CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE. 

i.  Chemical  Constitution. — In  its  chemical  composition,  cot- 
ton, in  common  with  the  other  vegetable  fibres,  consists  essentially 
of  cellulose.  On  the  surface  there  is  a  protecting  layer  of  more 
or  less  wax  and  oily  matter,  and  also  in  the  fibre  there  is  a  trace 
of  pigment,  which  in  some  varieties  of  cotton  becomes  quite 
emphasized.  The  removal  of  these  substances  is  the  object  of 
the  boiling-out  and  bleaching  processes  to  which  cotton  is  sub- 
jected prior  to  its  dyeing  and  printing.  In  reality,  the  purified 
cotton  fibre  as  it  exists  in  bleached  material  is  practically  pure 
cellulose,  and  this  compound  alone  appears  to  be  essential  to  its 
structural  organization. 

The  natural  impurities  present  in  the  raw  cotton  fibre  amount 
to  about  4  to  5  per  cent.,  and  consist  chiefly  of  pectic  acid,  color- 
ing-matter, cotton-wax,  cotton-oil,  and  albuminous  matter.  The 
fibre  gives  about  i  per  cent,  of  ash  on  ignition.*  The  oil  present 
in  the  fibre  appears  to  be  identical  with  cottonseed- oil,  and  is 
probably  obtained  from  the  seed  to  which  the  fibre  is  attached. 
The  cotton-wax  serves  as  a  protective  coating  for  the  fibre  and 
makes  it  water-repellent,  as  is  evidenced  by  me  long  time  it 
requires  for  raw  cotton  to  be  wetted  out  by  simply  steeping  in 
water.  This  wax  appears  to  be  closely  analogous  to  carnatiba 
wax ;  it  is  not  soluble  in  alkalies,  though  it  may  be  gradually  emul- 
sified by  a  long-continued  boiling  in  alkaline  solutions,  on  which 

*  Bowman  is  of  the  opinion  that  considerable  stress  should  be  laid  on  the 
fact  that  the  cotton  fibre  contains  about  i  per  cent,  of  mineral  matter  as  an  integral 
part  of  its  constitution,  and  this  no  doubt  has  considerable  influence  on  its  struc- 
ture and  properties. 

139 


140  THE   TEXTILE  FIBRES. 

fact  is  based  the  * '  boiling-out ' '  of  cotton  by  the  ordinary  methods. 
Cotton-wax,  however,  appears  to  be  readily  soluble  in  sulphated 
oils,  such  as  Turkey- red  oil,  and  hence  cotton  may  be  rapidly 
and  thoroughly  wetted  out  by  using  a  solution  of  such  an  oil. 
The  coating  of  wax  over  the  cotton  fibre  appears  to  influence  its 
spinning  qualities  to  a  certain  extent,  as  it  requires,  for  instance, 
a  rather  elevated  temperature  to  successfully  spin  fine  yarns,  in 
order  probably  to  soften  the  waxy  coating  of  the  fibre.*  The  fatty 
acid  present  in  cotton- wax  has  been  found  to  be  identical  with 
margaric  acid.  The  coloring-matter  of  cotton  has  been  investi- 
gated and  has  been  found  to  consist  of  two  organic  pigments, 
the  one  easily  soluble  in  alcohol,  and  the  other  only  dissolved  by 
boiling  alcohol.  According  to  Schunck,  the  composition  of  these 
bodies  from  Nankin  cotton  is  as  follows: 

A. — Soluble  in  B. — Insoluble  in 

Cold  Alcohol.  Cold  Alcohol. 

Per  Cent.  Per  Cent. 

Carbon 58.22  57-7° 

Hydrogen .  5.42  5 . 60 

Nitrogen 3.73  4 . 99 

Oxygen 32.63  31.71 

The  composition  of  the  analogous  coloring-matters  in  American 
cotton  is  practically  identical  with  the  above. 

Pectin  compounds  form  the  greater  portion  of  the  impurities 
present  in  cotton,  and  are  probably  rather  complex  in  nature. 

According  to  Dr.  Schunck,  American  cotton  contains  about 
0.48  per  cent,  of  fatty  matters,  whereas  East  Indian  cotton  con- 
tains only  0.337  Per  cent. 

Analysis  of  cotton-wax  shows  it  consists  of  the  following: 

Per  Cent. 

Carbon 80 . 38 

Hydrogen 14  •  5 1 

Oxygen 5.11 

*  As  the  temperature  falls  the  oily  wax  tends  to  become  stiff  and  gummy, 
and  prevents  the  proper  drawing  of  the  fibre;  while  its  presence  amongst  the 
thin  laminations  of  the  cell-walls  gives  a  greater  elasticity  to  the  fibre,  and  renders 
it  less  liable  to  sudden  rupture.  The  gradual  drying  up  of  the  more  volatile 
portions  of  this  oil  in  the  fibre,  leaving  the  remaining  portion  thicker  and  stiffer, 
may  also,  and  probably  does,  account  for  the  fact  noticed  by  most  spinners,  that 
new-crop  cotton  seems  to  work  better  and  makes  less  waste  than  as  the  season 
advances.  (Bowman,  "Cotton  Fibre,"  p.  55.) 


CHEMIC/tL  PROPERTIES  OF  COTTON;   CELLULOSE.          141 

It  fuses  at  85.9°  C.,  and  solidifies  at  82°  C.,  hence  it  bears  a 
close  analogy  to  both  cerosin,  or  sugar-cane  wax,  and  carnaiiba 
wax. 

The  quantity  of  ash  (mineral  matter)  in  raw  bale- cotton  will 
average  considerably  higher  than  that  obtained  from  the  purified 
fibre;  this  is  due  to  adhering  sand  and  dust  which  are  nearly 
always  present.  The  following  table  shows  the  amount  of  ash 
contained  in  samples  of  different  varieties  of  cotton : 

Per  Cent. 

Dharwar 4. 16 

Dhollerah 6.22 

Sea-island 1.25 

Peruvian  (soft) i .  68 

"         (rough) •. i .  15 

Bengal 3 . 98 

Broach 3 . 14 

Oomrawuttee 2.52 

Egyptian  (brown) i .  73 

(white) 1.19 

Pernam i .  60 

American 1.52 

When  the  amount  of  ash  is  found  to  be  over  i  per  cent,  the 
excess  may  be  considered  as  mechanically  attached  sand  and 
dust.  The  true  ash  of  the  cotton  fibre  consists  principally  of 
the  carbonates,  phosphates,  chlorides,  and  sulphates  of  potassium, 
calcium,  and  magnesium,  as  is  exhibited  by  the  following  analysis  ' 
of  Dr.  Ure: 

Per  Cent. 

Potassium  carbonate .* 44 . 80 

chloride. 9-9° 

sulphate 9-3° 

Calcium  phosphate 9 .  oo 

"        carbonate 10 . 60 

Magnesium  phosphate 8 . 40 

Ferric  oxide 3 .  oo 

Alumina  and  loss 5 .  oo 

The  analyses  of  Davis,  Dreyfus,  and  Holland,  reported  as  a 
mean  from  twelve  different  varieties  of  cotton,  show  a  little 
difference  from  the  above  analysis,  especially  in  having  present 
sodium  carbonate  as  one  of  the  constituents.  The  mean  of 
these  analyses  is  given  as  follows: 


142  THE   TEXTILE  FIBRES. 

Per  Cent. 

Potassium  carbonate 33-22 

chloride 10.21 

sulphate 13-02 

Sodium  carbonate 3-35 

Magnesium  phosphate 8 . 73 

carbonate 7.81 

Calcium  carbonate 20. 26 

Ferric  oxide 3 . 40 

The  albuminous  or  nitrogenous  matter  present  in  cotton 
is  only  of  very  small  amount,  and  doubtless  consists  of  protoplas- 
mic residue.  Different  varieties  of  cotton,  on  analysis,  show 
the  following  percentages  of  nitrogen;  some  of  this,  however, 
may  be  derived  from  mineral  nitrates  which  may  be  present  in 
slight  amount  in  the  fibre  (fiowman): 

Per  Cent  Nitrogen. 

American o .  030 

Sea -island o .  034 

Bengal o .  039 

Rough  Peruvian o .  033 

Egyptian  (white) o .  029 

(brown) o .  042 

Mean o .  0345 

Analyses  conducted  by  the  U.  S.  Department  of  Agriculture 
give  the  average  amount  of  nitrogen  present  in  cotton  as  0.34  pet 
cent.  As  this  differs  very  considerably  from  that  obtained  by 
Bowman,  it  may  be  possible  that  the  latter  must  be  multiplied 
by  ten  to  obtain  the  correct  figure. 

Church  and  Muller  have  made  careful  analyses  of  raw  cotton 
with  the  following  results: 

i.  ii. 

Cellulose 9l-l5  9T-35 

Hygroscopic  water 7.56  7 .  oo 

Wax  and  fat 0.51  0.40 

Nitrogen  (protoplasm) 0.67  0-50 

Cuticular  tissue o. 75 

Ash o.n  0.12 

2.  Cellulose. — This  is  one  of  the  most  important  of  the  natu- 
rally occurring  chemical  compounds,  as  it  forms  the  basis  of  all 
vegetable  tissue.  Chemically  it  consists  of  carbon,  hydrogen. 


CHEMICAL  PROPERTIES  OF  COTTON;   CELLULOSE.         143 

and  oxygen,  and  has  the  empirical  formula  C6H10O5.  It  belongs 
to  a  class  of  bodies  known  as  carbohydrates,  and  is  closely  related 
to  the  starches,  dextrins,  and  sugars.  Chemically  considered, 
these  compounds  must  all  be  regarded  as  alcohols  containing 
aldehydic  and  ketonic  groups.  The  word  cellulose  must  not 
be  taken  as  signifying  a  simple  definite  substance  of  unvarying 
properties,  but  rather  as  a  generic  term  including  quite  a  number 
of  bodies  of  similar  chemical  nature.  Like  starch  and  other 
complex  carbohydrates  of  organic  physical  structure,  cellulose 
will  vary  somewhat  in  its  properties,  depending  upon  its  source 
or  derivation.  As  a  class  the  celluloses  exhibit  certain  chemical 
characteristics,  by  means  of  which  they  may  be  distinguished 
from  associated  bodies  of  allied  chemical  constitution.  Physically 
they  are  colorless  amorphous  substances  capable  of  withstanding 
rather  high  temperatures  without  decomposition.  They  are 
insoluble  in  nearly  all  of  the  usual  solvents,  but  dissolve  more 
or  less  completely  in  an  ammoniacal  solution  of  copper  oxide 
(Schweitzer's  reagent).  Solution  in  this  latter  reagent  apparently 
takes  place  without  decomposition,  as  the  cellulose  may  be  re  pre- 
cipitated unchanged  therefrom  by  the  addition  of  acids  and 
various  salts.  In  order  to  obtain  pure  cellulose  for  chemical 
purposes  it  is  customary  to  treat  cotton  successively  with  dilute 
caustic  alkali,  dilute  acid,  water,  alcohol,  and  ether.  The  pur- 
pose of  this  treatment  is  to  remove  all  foreign  and  encrusting 
materials  from  the  raw  fibre,  and  possibly  also  to  remove  the 
thin,  external  cuticular  membrane  which  may  be  chemically 
different  from  the  rest  of  the  tissue.  The  specific  gravity  or 
density  of  cellulose  as  obtained  in  the  usual  manner  is  about  1.5, 
and  this  also  represents  the  density  of  cotton  and  most  other 
plant  fibres.  Chemically  considered,  cellulose  is  a  derivative 
of  the  open  chain  or  paraffin  series  of  hydrocarbons,  and  further- 
more it  exhibits  the  reactions  of  a  saturated  compound.  As 
with  the  other  carbohydrates,  chemists  have  found  it  a  matter 
of  great  difficulty  to  ascertain  even  approximately  the  true  mo- 
lecular formula  of  cellulose.  Though  its  empirical  formula  is 
C6H10O5,  this  in  no  way  represents  the  true  molecular  complexity 
of  the  substance.  From  a  study,  however,  of  its  various  synthet- 


144  THE   TEXTILE  FIBRES. 

ical  derivatives,  with  special  reference  to  its  esters,  such  as  the 
acetates,  benzoates,  and  nitrates,  the  provisional  formula  of 
C,  H20O10  has  been  given  to  the  cellulose  molecule.  The  nature 
and  position  of  the  various  organic  groups  present  in  this  mo- 
lecular formula,  however,  has  yet  to  be  worked  out.* 

In  its  chemical  reactions  cellulose  is  particularly  inert,  com- 
bining with  only  a  few  substances,  and  then  only  with  great  diffi- 
culty and  under  peculiar  conditions.  It  is  quite  resistant  to  the 
processes  of  oxidation  and  reduction,  and  hydrolysis  and  dehy- 
dration. Concentrated  sulphuric  acid  dissolves  cellulose  with 
the  production  of  a  viscous  solution;  dilution  with  water  causes 
the  precipitation  of  an  amorphous  substance  known  as  amyloid, 
a  starch-like  body  having  the  formula  C^H^On,  and  like  starch 
it  is  colored  blue  with  iodine.  On  this  reaction  is  based 
the  method  of  testing  for  cellulose,  by  applying  sulphuric  acid 
and  iodine.  On  boiling  with  dilute  sulphuric  acid,  cellulose  is 

*  Vignon  has  proposed  to  give  cellulose  the  following  constitutional  formula: 
O CHx 


v^ 

CH2— CH' 


(CHOH)3. 


This  is  based  on  a  study  of  the  highest  nitrate  of  cellulose  and  the  decomposi- 
tion of  the  nitrate  by  alkalies  with  formation  of  hydroxypyruvic  acid.  The  struc- 
ture given,  however,  is  more  or  less  hypothetical  in  nature,  and  needs  experimental 
confirmation  in  many  particulars  before  it  can  be  accepted  without  question. 
The  older  chemical  configuration  of  cellulose  given  by  Bowman, 

H  H     H 

I    I    I 

OH  OH  OH 

is  without  any  experimental  reason  for  its  existence,  and  the  idea  that  it  contains 
an  unsaturated  carbon  grouping,  —  C=  C  —  ,  has  been  proved  erroneous.  From 
a  study  of  the  osazones  of  oxycellulose,  Vignon  has  ascribed  to  this  latter  body 
the  constitutional  formula  of  the  group, 

OH 
(CHOH) 


/C 
)/ 


in  union  with  varying  proportions  of  residual  cellulose. 


CHEMICAL  PROPERTIES  OF  COTTON;  CELLULOSE.         145 

converted  into  dextrin  and  glucose.  On  heating  with  acetic 
anhydride  to  180°  C.,  cellulose  is  converted  into  an  acetyl  deriva- 
tive having  the  formula  C12H14O4(OCOCH3)6.  By  the  moderated 
action  of  concentrated  acids  and  various  acid  salts,  cellulose 
appears  to  undergo  a  process  of  hydration,  being  converted  into 
a  friable  amorphous  body  known  as  hydrocellulose.  This  reac- 
tion is  of  importance  in  the  carbonizing  process  for  removing 
vegetable  matter  from  woolen  goods. 

A  concentrated  solution  of  zinc  chloride  will  dissolve  cellulose 
on  heating  and  digesting  for  some  time.  This  solution  has  been 
employed  industrially  for  the  preparation  of  cellulose  filaments 
which  are  subsequently  treated  with  hydrochloric  acid  and 
washed  for  the  purpose  of  removing  the  zinc  salt;  the  thread  is 
then  carbonized  and  is  employed  for  the  carbon  filament  of  incan- 
descent electric  lamps.  A  concentrated  solution  of  zinc  chloride 
in  hydrochloric  acid  dissolves  cellulose  quite  rapidly  and  in  the 
cold.  This  latter  method  is  useful  in  the  laboratory  for  the  study 
of  celluloses,  but  as  yet  has  received  no  technical  application. 
By  means  of  this  solution  it  has  been  shown  that  the  cellulose 
molecule  does  not  contain  any  unsaturated  carbon  groups,  for 
it  exhibits  no  absorption  of  bromine.  A  solution  of  a  ligno- 
cellulose,  on  the  other  hand,  gives  a  marked  bromin  absorption', 
thus  showing  evidence  of  unsaturated  carbon  groups. 

Cellulose  is  colored  a  deep  violet  by  a  solution  of  zinc  chlor- 
iodide,  and  this  reagent  is  employed  as  a  delicate  test  for  the 
presence  of  cellulose.  The  reagent  may  be  best  prepared  by 
using  90  parts  of  a  concentrated  solution  of  zinc  chloride,  adding 
6  parts  of  potassium  iodide  in  10  parts  of  water,  and  iodin  until 
saturated. 

When  cellulose  is  treated  with  concentrated  caustic  alkalies 
it  undergoes  a  change  which  may  be  crudely  referred  to  as  "  mer- 
cerization,"  whereby  a  compound  known  as  alkali-cellulose  is 
formed,  in  which  the  molecular  ratio  of  alkali  to  cellulose  may 
be  given  as  C12H20O10  :NaOH.  When  this  body  is  treated  with 
carbon  disulphide  a  substance  known  as  cellulose  thiocarbonate  or 
xanthate  is  formed.  This  body  yields  a  very  viscous  solution 
with  water  and  has  been  utilized  for  various  technical  purposes 


146  THE   TEXTILE  FIBRES. 

(see  viscose).  Cellulose  xanthate  undergoes  spontaneous  decom- 
position, splitting  up  into  cellulose  hydrate,  alkali,  and  carbon 
disulphide;  this  cellulose  hydrate  is  also  known  as  regenerated 
cellulose.  This  ,  substance  can  also  be  precipitated  by  the 
addition  of  various  salts,  such  as  ammonium  chloride.  Alkali- 
cellulose  also  reacts  with  benzoyl  chloride  with  the  formation  of 
cellulose  benzoate.  Another  ester  of  cellulose  is  the  acetate,  which 
can  be  made  by  the  action  of  acetic  anhydride  on  cellulose  heated 
in  a  sealed  tube;  regenerated  cellulose  can  also  be  employed. 
By  varying  the  conditions  of  treatment  a  number  of  different 
acetates  have  been  prepared.  The  tetr acetate  has  received  a 
number  of  commercial  applications  for  the  production  of  films 
and  for  waterproofing.  By  the  action  of  nitric  acid  under  vary- 
ing conditions  a  number  of  cellulose  nitrates  (improperly  called 
nitrocelluloses)  have  been  prepared,  which  have  received  numer- 
ous applications  (see  pyroxylin).  Concentrated  sulphuric  acid 
reacts  with  cellulose  to  form  at  first  a  cellulose  sulphate;  this 
subsequently  undergoes  decomposition  with  a  consequent  hy- 
drolysis of  the  cellulose  molecule  and  the*  formation  of  amy- 
loid. 

Although  cellulose  is  comparatively  inert  to  the  majority  of 
chemical  reagents,  it  has  a  powerful  attraction  for  certain  salts 
held  in  solution  and  will  absorb  them  completely.  This  power 
of  absorption  is  especially  marked  towards  salts  .of  vanadium, 
these  being  completely  separated  from  solutions  containing  only 
one  part  of  the  salt  in  a  trillion. 

Besides  cellulose  itself,  there  are  a  number  of  derived  sub- 
stances which  are  known  as  compound  celluloses.  These  are 
classified  into  three  general  groups: 

(a)  Pectocelluloses,  related  to  pectin  compounds  of  vegetable 
tissues;    represented  among  the  fibres  by  raw  flax;    resolved  by 
hydrolysis  with  alkalies  into  pectic  acid  and  cellulose. 

(b)  LignoceUuloscs,  forming  the  main  constituent  of  woody  tis- 
sue and  represented  among  the  fibres  by  jute;  resolved  by  chlorina- 
tion  into  chlorinated  derivatives  of  aromatic  compounds  soluble 
in  alkalies  and  cellulose. 

(c)  Adipocellulosesy  forming  the  epidermis  or  cuticular  tissue 


CHEMICAL  PROPERTIES  OF  COTTON;   CELLULOSE.         147 

of  fibres,  leaves,  etc.;  resolved  by  oxidation  with  nitric  acid  into 
derivatives  similar  to  those  of  the  oxidation  of  fats  and  cellulose. 

Fre'my  groups  the  various  celluloses  and  their  derived  bodies 
in  the  following  manner,  which  is  based  on  a  chemical  classifica- 
tion: (a)  celluloses,  including  normal  cellulose,  paracellulose,  and 
metacellulose;  (b)  vasculose  (identical  with  lignocellulose) ;  (c) 
cutose;  (d)  pectose. 

3.  Chemical  Reactions  of  Cotton. — Cotton  itself  presents  the 
same  general  reactions  and  chemical  properties  as  cellulose.  It 
is  capable  of  standing  rather  high  temperatures  without  decom- 
position or  alteration;  though  it  appears  that  when  cotton  is  sub- 
jected to  a  temperature  of  160°  C.,  whether  moist  or  dry  heat, 
a  dehydration  of  the  cellulose  takes  place,  accompanied  by  a 
structural  disintegration  of  the  fibre.  This  fact  has  an  important 
bearing  on  the  singeing,  calendering,  and  other  finishing  processes 
where  high  temperatures  are  used.  At  250°  C.  cotton  begins  to 
turn  brown;  and  when  ignited  in  the  air  it  burns  freely,  emitting 
an  odor  faintly  suggesting  acrolein,  but  without  the  characteristic- 
ally empyreumatic  odor  of  burning  animal  fibres.  When  sub- 
jected to  dry  distillation  cotton  is  decomposed  into  methane, 
ethane,  water,  methyl  alcohol,  acetone,  acetic  acid,  carbon  dioxide, 
pyrocatechol,  etc.  Though  unaltered  and  insoluble  in  boiling 
water,  when  heated  with  water  under  pressure  to  200°  C.  it  is 
dissolved  with  complete  decomposition. 

Like  cellulose  itself,  cotton  is  dissolved  by  Schweitzer's  reagent, 
though  under  ordinary  conditions  its  solution  is  a  rather  slow 
process.  In  order  to  dissolve  cotton  most  effectively  in  ammonia- 
cal  copper  oxide,  it  is  recommended  to  treat  the  raw  cotton  with  a 
strong  solution  of  caustic  soda  until  the  fibres  swell  up  and  become 
translucent;  squeeze  out  the  excess  of  liquid,  and  wash  the  cotton 
with  strong  ammonia  water;  then  treat  with  the  solution  of 
ammoniacal  copper  oxide  and  the  cotton  will  be  found  to  dissolve 
quite  rapidly.  This  solution  may  furthermore  be  filtered  and 
diluted  with  water.  The  use  of  this  solution  for  the  production 
of  lustra-cellulose  filaments  has  received  some  degree  of  com- 
mercial application  (see  Pauly  silk).  This  reaction  is  also  util- 
ized in  the  production  of  the  so-called  Willesden  canvas;  the 


148  THE   TEXTILE  FIBRES. 

cotton  fabric  is  passed  through  a  solution  of  ammoniacal  copper 
oxide,  whereby  the  surface  becomes  coated  with  a  film  of  par- 
tially dissolved  gelatinized  cellulose  containing  a  considerable 
amount  of  copper  oxide.  On  subsequent  hot  pressing  this  film 
is  fixed  on  the  surface  of  the  material  as  a  substantial  coating, 
which  is  said  to  make  the  canvas  water-proof  and  render  it  un- 
affected by  mildew  and  insects. 

Concentrated  solutions  of  zinc  chloride  are  capable  of  dis- 
solving cotton,  but  only  after  a  prolonged  digestion  at  about 
100°  C.,  though  by  first  treating  the  cotton  with  caustic  alkali 
the  solution  takes  place  in  the  cold.  The  product  so  obtained 
has  received  several  industrial  applications;  vulcanized  fibre  is 
prepared  by  dissolving  paper  in  a  concentrated  solution  of  zinc 
chloride,  and  the  resulting  gelatinous  mass  is  manufactured 
into  various  articles,  such  as  blocks,  sheets,  etc.  The  chief 
difficulty  encountered  is  the  subsequent  removal  of  the  zinc  salt, 
which  necessitates  a  very  lengthy  process  of  washing.  The  ma- 
terial may  be  rendered  water-proof  by  a  further  process  of  nitra- 
tion.* The  solution  has  also  been  suggested  for  use  as  a  thick- 
ening agent  in  calico-printing.  Its  use  for  the  production  of 
lustra-cellulose  or  artificial  silk  and  incandescent  lamp  filaments 
has  also  been  attempted. 

With  mineral  acids  cotton  exhibits  practically  the  same  gen- 
eral reactions  as  pure  cellulose.  Concentrated  sulphuric  acid 
produces  amyloid  in  the  manner  already  mentioned,  and  this 
fact  is  utilized  in  the  preparation  of  what  is  known  as  vegetable 
parchment.  Unsized  paper  is  rapidly  passed  through  concentrated 
sulphuric  acid,  then  thoroughly  washed  and  dried.  The  effect  of 
this  treatment  is  to  cause  the  formation  on  the  surface  of  the 
paper  of  a  layer  of  gelatinous  amyloid,  which  on  subsequent 
pressing  and  drying  gives  a  tough  membranous  surface  to  the 
paper  resembling  true  parchment.  This  renders  the  paper  grease- 
proof and  water-proof,  and  increases  its  tensile  strength  con- 
siderably. Artificial  horse-hair  has  been  prepared  in  a  similar 
manner  from  certain  Mexican  grasses.  These  latter  are  steeped 
for  a  short  time  in  concentrated  sulphuric  acid,  and  become 

*  Hofmann,  Handb;-d.   Papierfab.,  p.   1703. 


CHEMICAL  PROPERTIES   OF  COTTON;  CELLULOSE.          149 

parchmentized  thereby,  so  that  on  being  subsequently  washed 
and  combed  they  assume  an  appearance  very  much  resembling 
horse-hair,  and  are  said  to  possess  even  greater  elasticity  than 
horse-hair  itself.  In  place  of  strong  sulphuric  acid  a  solution  of 
zinc  chloride  may  be  used  with  similar  results.  Amyloid  appears 
also  to  be  a  product  of  natural  plant  growth,  as  its  presence  has 
been  detected  in  the  walls  of  vegetable  cells;  it  may  be  recog- 
nized by  giving  a  blue  color  with  iodine. 

Very  dilute  solutions  of  sulphuric  acid,  especially  in  the  cold, 
have  no  appreciable  action  on  cotton.  But  if  the  fibre  is  impreg- 
nated with  such  a  solution  and  then  allowed  to  dry  it  becomes 
rapidly  tendered;  this  is  owing  to  the  gradual  concentration 
of  the  acid  in  the  fibre  on  drying.  Elevated  temperatures  also 
cause  the  dilute  acid  to  attack  the  fibre  much  more  quickly  and^ 
severely  than  otherwise. 

In  all  dyeing  and  bleaching  operations  where  the  use  of  acid 
may  be  required  the  above  facts  should  always  be  borne  in 
mind;  the  temperature  of  the  acid  baths  should  not  be  above 
70°  F.,  and  the  acid  strength  should  not  be  more  than  2  per 
cent.  Where  higher  temperatures  are  necessary  organic  acids 
should  be  substituted  for  mineral  acids  wherever  possible.  Acetic 
acid,  for  instance,  is  often  used.  Whenever  cotton  is  treated 
with  acid  solutions  or  with  salts  of  an  acid  nature  or  which  are 
liable  to  decompose  with  liberation  of  acid,  all  of  the  acid  should 
be  removed  from  the  fibre  or  properly  neutralized  before  drying, 
else  the  material  will  be  tendered  and  probably  ruined.  The 
action  of  dilute  acid  on  cotton  is  probably  an  hydrolysis  of  the 
cellulose  molecule,  with  the  formation  of  hydroxycellulose,  causing 
a  structural  disorganization  of  the  fibre  to  take  place.  Hydro- 
chloric acid  has  an  effect  similar  to  sulphuric  acid,  and  the  same 
remarks  concerning  the  use  of  this  latter  acid  in  connection 
with  cotton  also  hold  true  for  the  former.  Strong  nitric  acid  has 
a  somewhat  different  effect;*  it  completely  decomposes  cotton,  in 

*  The  action  of  nitric  acid  on  cotton  fabrics  appears  to  be  a  peculiar  one.  The 
following  observations  in  this  respect  have  been  recorded  by  Knecht:  Bleached 
calico  steeped  for  fifteen  minutes  in  pure  nitric  acid  at  80°  Tw.,  washed,  and  dried, 
showed  a  considerable  contraction,  amounting  to  about  24  per  cent.;  the  tensile 


150  THE   TEXTILE  FIBRES. 

common  with  other  forms  of  cellulose,  oxidizing  it  to  oxalic 
acid.  When  boiled  with  moderately  concentrated  nitric  acid 
cotton  is  converted  into  oxycellulose,  a  structureless,  friable 
substance  possessing  a  great  affinity  for  basic  dyestuffs.  When 
mixed  with  concentrated  sulphuric  acid,  however,  the  action 
of  nitric  acid  is  totally  different,  the  cellulose  being  converted 
into  a  nitro-derivative,  though  the  physical  appearance  of  the 
fibre  is  not  appreciably  altered.  The  exact  nature  of  the  nitrated 
compound  will  depend  on  the  conditions  of  treatment.  Several 
nitrocelluloses  are  known  and  possess  commercial  importance; 
they  are  classified  under  the  general  name  of  pyroxylins.  Gun- 
cotton,  a  hexanitrocellulose,  is  the  most  highly  nitrated  product, 
and  is  used  as  a  basis  of  many  explosives.  Soluble  pyroxylin  is 
a  trinitrocellulose ;  its  solution  in  a  mixture  of  alcohol  and  ether 
is  called  collodion  and  is  employed  in  surgery  and  photography. 
Another  derivative,  supposed  to  be  a  tetranitrocellulose,  is  also 
soluble  in  ether-alcohol,  and  its  solution  has  been  utilized 
for  the  production  of  lustra-cellulose  filaments.  By  dissolving 
nitrocellulose  in  molten  camphor  a  substance  known  as  celluloid 
is  formed. 

The  action  of  hydrofluoric  acid  on  cotton  and  other  vegetable 
fibres  appears  to  be  a  peculiar  one;  a  transparent,  tough,  flexible 
water-proof  material  being  obtained.  The  product  does  not 
appear  to  resemble  parchment  obtained  by  the  action  of  sulphuric 
acid.  It  is  used  as  an  insulating  material  and  for  making  the 
carbon  filaments  of  incandescent  electric  lamps. 

Organic  acids  in  solution,  even  when  moderately  concentrated, 

strength  also  increased  78  per  cent.  Unbleached  yarn,  treated  in  the  same  manner, 
also  showed  a  considerable  increase  of  tensile  strength,  and  a  proportional  con- 
traction in  length.  Weaker  acids  did  not  show  these  results,  the  fibre  being 
tendered  instead  of  being  strengthened.  Analysis  proved  that  7.7  per  cent,  of 
nitrogen  was  present,  showing  that  about  two  molecules  of  the  acid  had  combined 
with  the  cotton.  The  shrinkage,  gain  in  strength,  microscopical  appearance, 
the  treated  material,  all  go  to  show  that  in  addition  to  the  nitration  a  mer- 
crri/.ing  effect  has  been  produced.  This  appears  in  the  fact  that  the  material 
exhibits  a  strongly  increased  affinity  for  many  dyestuffs,  especially  the  direct 
cotton  colors  and  some  of  the  acid  dyes;  while  by  reason  of  its  not  showing  any 
increased  affinity  for  the  basic  colors  there  is  proof  that  oxycellulose  has  not 
been  produced. 


CHEMICAL  PROPERTIES  OF  COTTON;  CELLULOSE.          151 

do  not  appear  to  have  any  injurious  action  on  cotton.  The  non- 
volatile acids,  however,  such  as  oxalic,  tartaric,  and  citric  acids, 
when  allowed  to  dry  into  the  fibre,  act  much  in  the  same  manner 
as  mineral  acids,  especially  at  elevated  temperatures.*  Acetic 
acid,  however,  being  volatile,  exerts  no  destructive  action;  hence 
this  latter  acid  is  particularly  suitable  for  use  in  the  dyeing  and 
printing  of  cotton  goods,  where  the  use  of  an  acid  is  requisite.! 

Tannic  acid,  unlike  other  acids,  exhibits  quite  an  affinity  for 
cotton,  the  latter  being  capable  of  absorbing  as  much  as  7  to  10 
per  cent,  of  its  weight  of  tannic  acid  from  an  aqueous  solution. 
Advantage  is  taken  of  this  fact  in  the  mordanting  of  cotton  with 
tannic  acid  and  tannins  for  the  dyeing  and  printing  of  basic 
colors.  Cotton  exhibits  a  similar  attraction  for  tungstic  acid; 
the  expense  of  this  latter  compound,  however,  precludes  its 
adoption  as  a  mordanting  agent. 

Though  acids,  in  general,  have  such  an  injurious  action  on 
cotton,  alkalies,  on  the  other  hand,  are  harmless  under  ordinary 
conditions.  Dilute  solutions  of  either  the  carbonated  or  caustic 
alkalies,  even  at  a  boiling  temperature,  if  air  is  excluded,  have 
no  injurious  effect  on  cotton.  In  the  presence  of  air  alkaline 
solutions  cause  an  hydrolysis  of  the  cellulose  in  a  manner  similar 
to  acids,  with  the  result  that  the  fibre  is  seriously  weakened. 
This  action  of  alkalies  in  the  presence  of  air  is  an  important 
one  to  bear  in  mind  in  the  operations  of  bleaching,  dyeing,  or 
mercerizing  which  will  be  subsequently  studied.  Boiling  solu- 


*  The  destructive  action  of  these  acids  on  the  cotton  fibre  is,  perhaps,  not 
so  much  of  a  chemical  nature  as  mechanical,  it  being  caused  by  the  acids  crystal- 
lizing within  the  fibre  and  thus  breaking  the  cell-wall.  A  dry  heat,  for  instance, 
in  connection  with  these  acids  is  much  more  injurious  than  a  moist  heat,  a  fact 
which  is  of  much  importance  in  the  drying  of  cotton  prints,  where  the  above- 
mentioned  acids  may  have  been  used. 

f  Oxalic  acid  appears  to  have  a  peculiar  effect  on  cotton;  it  has  been  noticed 
that  if  a  piece  of  cotton  cloth  be  printed  with  a  thickened  solution  of  oxalic  acid, 
dried,  and  hung  in  a  cool  place  for  about  twelve  hours,  and  then  well  washed, 
the  printed  parts  exhibit  a  direct  affinity  towards  the  basic  dyes.  The  cotton 
so  treated  does  not  become  tender  or  otherwise  changed.  Towards  substantive 
dyes  it  exhibits  considerably  .less  attraction  than  ordinary  cotton,  while  with  alizarin 
dyes  it  is  partially  reactive.  Tartaric  and  citric  acids  do  not  produce  the  same 
effect,  nor  does  the  neutral  or  acid  oxalate  of  potassium. 


THE    TEXTILE  hIBRES. 


tions  of  dilute  alkalies  dissolve  or  emulsify  the  waxy  and  fatty 
impurities  encrusting  the  cotton  fibre,  hence  these  reagents  are 
largely  employed  in  the  scouring  of  cotton  goods. 

The  action  of  alkaline  solutions  at  high  temperatures  (above 
100°  C.)  on  cotton  appears,  however,  to  be  a  destructive  one. 
Tauss  has  shown  that  if  cotton  be  digested  with  solutions  of 
caustic  soda  under  pressure,  the  fibre  is  attacked  and  converted 
into  soluble  products;  the  degree  of  decomposition  depending 
on  the  pressure  and  the  strength  of  the  alkaline  liquor,  in  accord- 
ance with  the  following  table: 


Pressure. 

Strength  of  Alkali. 

3%  Na20. 

8%  Na20. 

PerCent   Dissolved. 

I 

5 

10 

atmosphere 

12.  I 

15-4 
20.3 

22.0 
58.0 

59-o 

a  tmospheres 

Solutions  of  ammonia  do  not  act  on  cotton  until  quite  high 
temperatures  are  reached.  According  to  the  experiments  of  L. 
Vignon,  at  200°  C.  ammonia  reacts  with  cotton  cellulose,  the 
result  being  the  evident  formation  of  an  amidocellulose  com- 
pound, the  product  evincing  a  greatly  increased  degree  of  absorp- 
tion for  dyestuff  solutions,  especially  for  the  acid  coloring-matters, 
somewhat  after  the  manner  of  animal  fibres. 

This  action  of  alkaline  solutions  on  cotton  under  rijr  pressure 
has  an  important  bearing  on  the  bleaching  of  this  fibre,  jvhere  it 
is  subjected  to  such  action  by  boiling  with  alkalies  in  pressure 
kiers.  This  phase  of  the  question  does  not  appear  to  have  re- 
ceived much  attention  from  either  the  practical  bleacher  or  the 
theoretical  chemist,  but  it  would  seem  to  be  worthy  of  some  degree 
of  intelligent  research  on  the  part  of  both. 

Concentrated  solutions  of  caustic  alkalies  have  a  peculiar 
effect  on  cotton;  the  fibre  swells  up,  becomes  cylindrical  and 
semi-transparent,  while  the  interior  canal  is  almost  entirely  oblit- 
erated by  the  swelling  of  the  cell-walls.  There  is  a  marked  gain 


CHEMICAL  PROPERTIES  OF  COTTON;  CELLULOSE.          153 

in  weight  and  strength,  while  the-  affinity  of  the  cotton  for  coloring- 
matters  is  materially  increased.  This  effect  was  first  noticed  by 
John  Mercer  in  1844,  and  the  reaction  forms  the  basis  of  the 
modern  process  of  mercerizing,  under  which  title  a  more  com- 
plete and  extensive  discussion  of  this  reaction  will  be  found. 
Solutions  of  sodium  sulphide  appear  to  have  no  immediate  ten- 
dering action  on  cotton,  even  at  a  boiling  temperature.  If  the 
sodium  sulphide  is  dried  into  the  fibre  after  about  six  weeks  the 
cotton  shows  a  loss  in  strength  of  from  10  to  20  per  cent.  Also, 
when  sodium  sulphide  is  dried  in  the  fibre  at  100°  C.,  the  tender- 
ing amounts  to  from  10  to  20  per  cent.  Cotton  containing  copper 
sulphide  or  iron  sulphide  shows  no  appreciable  amount  of  tender- 
ing. When  cotton  is  impregnated  with  sulphur  and  exposed  to  a 
damp  atmosphere  for  several  weeks  its  tensile  strength  is  reduced 
by  about  one-half.  This  is  perhaps  due  to  the  oxidation  of  the 
sulphur  into  sulphurous  and  sulphuric  acids. 

If  cotton,  or  other  forms  of  cellulose,  be  treated  with  a  concen- 
trated solution  of  caustic  soda  to  which  a  small  amount  of  carbon 
disulphide  has  been  added,  the  fibres  swell  up,  become  disinte- 
grated, and  finally  form  a  gelatinous  mass.  This  latter  is 
soluble  in  a  large  amount  of  water,  producing  a  very  viscous 
solution,  technically  known  as  viscose.  From  this  solution  hydro- 
cellulose  may  be  precipitated  by  sulphurous  acid  gas,  as  well  as 
by  various  other  reagents.  Precipitation  also  occurs  by  simply 
allowing  the  solution  to  stand  for  some  time,  in  which  case  the 
hydrocellulose  separates  out  as  a  jelly-like  mass.  Viscose  has 
received  several  commercial  applications,  among  which  may  be 
mentioned  more  especially  the  use  of  its  solutions  for  the  prepara- 
tion of  lustra-cellulose  filaments. 

Though  cotton  does  not  show  nearly  the  same  degree  of  affin- 
ity for  acids  and  alkalies  as  do  the  animal  fibres,  nevertheless  it . 
has  been  shown  that  cotton  does  absorb  both  acids  and  alkalies 
from  their  solutions,  even  when  cold  and  dilute.  The  ratio  of 
absorption  appears  to  be  3  molecular  parts  of  acid  to  10  molecular 
parts  of  caustic  alkali.  Vignon,  by  a  study  of  the  thermochem- 
ical  reactions  of  cotton,  has  shown  that  when  this  fibre  is  treated 
with  acids  or  alkalies  a  liberation  of  heat  takes  place,  from  which 


154  THE   TEXTILE  FIBRES. 

fact   it  would  appear  that  cotton  exhibits  in  some  degree  the 
properties  of  a  very  weak  acid  and  a  still  weaker  base. 

Strong  oxidizing  agents,  such  as  chromic  acid,  permanganates, 
chlorin,  etc.,  in  concentrated  solutions,  readily  attack  cotton, 
converting  it  into  oxycellulose.  This  substance  appears  to  pos- 
sess an  increased  affinity  for  dyestufTs,  but  it  is  of  a  structureless 
and  brittle  nature,  hence  its  formation  greatly  tenders  the  fibre. 
It  is  said  that  oxycellulose  is  indifferent  towards  the  tetra/o 
dyestuffs;  and,  in  consequence,  these  may  be  employed  for  the 
purpose  of  detecting  the  presence  of  oxycellulose  in  cotton  mate- 
rials. 

In  its  action  towards  various  metallic  salts  cotton  is  very  neu- 
tral, thereby  differing  considerably  from  both  wool  and  silk.  If 
the  salts,  however,  are  present  in  a  very  basic  condition,  cotton 
is  capable  of  decomposing  them  and  loosely  fixing  the  metallic 
hydroxide.  Many  salts,  especially  those  of  an  acid  nature,  will 
tender  the  cotton  fibre,  probably  due  to  the  liberation  and  drying 
in  of  the  acid.  Consequently  such  salts  should  be  avoided  or 
used  very  carefully  with  cotton,  and  any  excess  should  be  thor- 
oughly eliminated  by  subsequent  washing  before  the  material 
dries. 

In  its  behavior  towards  coloring- matters  cotton  differs  most 
markedly  from  the  animal  fibres.  Of  the  natural  dyestuffs,  only 
a  few  color  the  cotton  fibre  without  a  mordant;  with  the  coal-tar 
colors,  cotton  exhibits  no  affinity  for  most  of  the  acid  or  basic 
dyes,  and  these  can  only  be  applied  on  a  suitable  mordant.  The 
substantive  colors,  however,  are  readily  dyed  on  cotton,  in  a 
direct  manner,  and  since  their  introduction  the  methods  of  cotton 
dyeing  have  been  practically  revolutionized. 

Though  resistant  to  the  action  of  moths  and  insects  in  general, 
cotton  is  liable  to  undergo  fermentation,  as  is  evidenced  by  the 
formation  of  mildew  on  cotton  fabrics  stored  in  damp  places. 
Though  this  fermentation  is  often  induced  by  the  presence  of 
more  or  less  starchy  matter  contained  in  the  sizing  materials 
used  in  finishing  the  goods,  yet  pure  cellulose  itself  can  also  be 
fermented,  and  Omeliansky  has  succeeded  in  isolating  the  par- 
ticular bacillus  which  destroys  cellulose. 


CHEMICAL  PROPERTIES  OF  COTTON;  CELLULOSE.          155 


There  has  been  much  discussion  as  to  whether  the  various 
treatments  to  which  cotton  is  subjected  during  the  process  of 
bleaching  has  any  deleterious  effect  on  the  strength  of  the  fibre. 
In  this  connection  O'Neill  gives  the  following  interesting  results, 
made  to  determine  the  tensile  strength  of  cotton  threads  before 
and  after  bleaching : 


Average  Weight  Required  to  Break 
a  Single  Thread. 

Before  Bleaching. 

After  Bleaching. 

No. 
No. 
No. 
No. 

i  cloth,  weft-threads  

1714  grains 

3MO      " 
3407      " 
3512 

2785  grains 
2020      " 
3708      « 
4025      " 

i      "      warp-threads  

2        "                     " 

2        "                     " 

It  will  be  noticed  that  in  two  cases  out  of  three  the  warp-threads 
are  stronger  than  before,  and  it  may  be  safely  concluded  that  the 
tensile  strength  of  cotton  yarn  is  not  injured  by  careful  though 
thorough  bleaching,  and  probably  it  may  be  strengthened  by  the 
wetting  and  pressure  causing  a  more  complete  and  effective  bind- 
ing of  the  separate  cotton  fibres,  the  twisting  together  of  which 
makes  the  yarn  stronger. 


CHAPTER  XII. 

MERCERIZED  COTTON. 

i.  Mercerizing  is  a  term  applied  to  that  process  whereby 
cotton  is  treated  with  concentrated  caustic  alkalies.  In  its 
strictest  significance,  however,  it  refers  most  directly  to  the 
process  of  giving  cotton  a  high  degree  of  lustre  by  subjecting  it 
simultaneously  to  the  chemical  action  of  caustic  alkalies  and  the 
mechanical  action  of  strong  tension  sufficient  to  prevent  con- 
traction. The  process  is  named  from  John  Mercer,  who  first 
discovered  the  effect  of  strong  solutions  of  caustic  alkalies  on 
cotton  in  the  year  1844.  It  was  not  until  the  last  decade,  how- 
ever, that  the  process  attained  any -degree  of  commercial  success; 
but  during  the  last  few  years  it  has  given  practically  a  new  fibre 
to  the  textile  industry. 

Mercerizing,  in  its  essential  meaning,  relates  to  the  action  of 
certain  chemicals  on  cellulose  whereby  the  latter  is  changed  to 
a  product  known  as  cellulose  hydrate;  though,  technically,  the 
term  has  come  to  mean  the  process  concerned  with  the  imparting 
of  a  silk-like  lustre  to  the  fibre.  As  generally  understood,  it 
consists  briefly  in  impregnating  cotton  yarn  or  cloth  with  a  rather 
concentrated  cold  solution  of  caustic  soda  and  subsequently 
washing  out  the  caustic  liquor  with  water,  the  material  being 
either  held  in  a  state  of  tension  during  the  time  it  is  treated  with 
the  caustic  alkali  in  order  to  prevent  contraction,  or  stretched 
back  to  its  original  length  after  treatment  wth  the  alkali,  but 
previous  to  washing.  In  either  case,  tin-  mate-rial  must  be  in  a 
state  of  tension  during  the  process  of  washing.  There  are  two 
separate  phases  of  the  mercerizing  process  represented  in  the 

156 


MERCERIZED   COTTON.  157 

above  operations  which  must  be  separately  understood  in  order 
to  comprehend  the  exact  nature  of  the  change  which  takes  place 
in  the  appearance  of  the  fibre;  the  one  is  the  chemical  action  of 
the  caustic  soda,  and  the  other  is  the  mechanical  effect  brought 
about  by  the  tension.  The  action  of  the  caustic  alkali  is  to  effect 
a  chemical  transformation  in  the  substance  of  the  fibre,  a  further 
chemical  reaction  taking  place  when  this  product  is  treated  with 
water.  As  already  pointed  out  (p.  145),  cellulose  has  the  prop- 
erty of  combining  with  caustic  soda  to  form  a  product  known  as 
alkali-cellulose,  C^H2QOIQ :  NaOH.  The  formation  of  this  com- 
pound does  not  appear  to  disintegrate  the  organic  structure  of 
the  fibre-cell,  provided  the  proper  conditions  are  maintained. 
The  alkali-cellulose,  however,  is  apparently  a  rather  feebly  com- 
bined molecular  aggregate,  and  does  not  exhibit  much  stability 
towards  reagents  in  general.  It  is  even  decomposed  by  the  action 
of  water,  the  effect  of  the  latter  being  to  disrupt  the  bond  of  molec- 
ular union  between  the  alkali  and  cellulose,  with  the  consequent 
re- formation  of  caustic  soda  and  the  introduction  of  water  into  the 
cellulose  molecule.  This  latter  substance,  which  may  be  termed 
cellulose  hydrate,  forms  the  chemical  basis  of  mercerized  cotton. 
The  theory  that  caustic  soda  effects  a  true  chemical  combination 
\vit-h  cellulose  is  somewhat  supported  by  the  fact  that  mercerized 
cotton  undergoes  chemical  changes  to  which  ordinary  cotton  is 
not  susceptible.  For  instance,  the  former  is  much  more  readily 
dissolved  by  a  solution  of  ammonio-copper  oxide;  it  is  chem- 
ically reactive  with  carbon  disulphide  with  the  formation  of 
soluble  cellulose  thiocarbonates ;  alkali-cellulose  also  reacts  with 
benzoyl  chloride  and  acetic  anhydride,  giving  rise  to  cellulose 
benzoates  and  acetates.  The  nature  of  the  chemical  change  from 
ordinary  to  mercerized  cotton,  however,  is  rather  ill-defined; 
it  no  doubt  can  be  included  under  that  class  of  reactions  which 
stands  somewhat  midway  between  ordinary  physical  and  chem- 
ical changes,  and  is  to  be  particularly  observed  in  connection 
with  those  bodies  possessing  a  high  degree  of  molecular  com- 
plexity, such  as  various  colloidal  substances,  and  the  large  num- 
ber of  naturally  occurring  carbohydrates,  starches,  gums,  etc. 
The  fact  that  there  is  no  evidence  of  disorganization  in  the  fibre- 


158  THE   TEXTILE  FIBRES. 

cell,  as  may  be  observed  from  its  physical  properties  and  micro- 
scopic appearance,  is  a  strong  argument  against  true  chemical 
change,  which  would  necessitate  a  rearrangement  in  the  atomic 
grouping  in  the  substance  of  the  fibre.  This  would  result  in  a 
decomposition  of  its  organized  structure,  which  would  at  once 
be  manifested  in  a  decrease  in  the  tensile  strength,  and  a  gradual 
breaking  down  of  the  fibre  itself.  But  mercerized  cotton  shows 
no  such  change;  on  the  other  hand,  its  tensile  strength  is  con- 
siderably increased,  and  the  fibre-cell  shows  no  tendency  towards 
physical  decomposition. 

When  the  cotton  fibre  is  immersed  in  a  concentrated  solution 
of  caustic  soda  it  undergoes  a  peculiar  physical  modification;  it 
appears  to  absorb  the  alkali,  swelling  up  to  a  cylindrical  form,  so 
that  it  presents  more  the  appearance  of  a  hair  than  a  flat  ribbon; 
the  fibre  also  untwists  itself  and  becomes  much  straighter,  at 
the  same  time  shrinking  considerably  in  length.  The  internal 
portion  of  the  fibre  acquires  a  gelatinous  appearance,  becom- 
ing somewhat  translucent  to  light,  though  it  is  firm  in  structure; 
the  external  surface  of  the  fibre  shows  a  wrinkled  appearance 
transversely,  due  to  a  somewhat  unequal  distension  of  the  inner 
part. '  There  is  a  small  degree  of  lustre  on  portions  of  the  surface, 
but,  due  to  the  uneven  stretching  and  wrinkling  of  the  external 
superficies,  the  smooth  lustrous  portions  are  irregular  in  occur- 
rence and  not  very  extensive  in  area.  The  fibre  also  shows  a 
-light  increase  in  weight.  These  changes  in  the  physical  appear- 
ance of  the  fibre  are  accompanied  by  a  remarkable  increase  in 
the  tensile  strength,  amounting  in  most  cases  to  as  much  as  30  to 
50  per  cent.;  the  fibre  also  acquiring  a  greater  power  of  absorp- 
tion towards  many  solutions,  most  notably  those  of  dyestuffs. 
The  increase  in  tensile  strength  is  probably  due  to  the  fact  that 
mercerizing  causes  the  inner  structure  of  the  fibre  to  become- 
more  solidly  bound  together  by  a  filling  up  of  the  interstitial 
spaces  between  the  molecular  components  of  the  cell-wall.  In 
this  manner  the  fibre  as  a  whole  is  given  a  greater  degree  of 
solidity;  the  internal  strain  between  the  cell  elements  (which 
must  be  quite  considerable  after  the  drying  out  and  shrinking 
of  the  ripened  fibre)  is  lessened  no  doubt,  and  hence  adds  to  the 


MERCERIZED   COTTON.  159 

unified  strength  of  the  fibre.  From  the  fact  that  the  fibre  shrinks 
in  length  in  mercerizing,  it  is  probable  that  the  cell  elements  have 
contracted  transversely  on  the  collapse  of  the  fibre  canal,  and 
on  being  distended  again  by  the  action  of  the  caustic  alkali 
these  cell  elements  become  shortened  longitudinally,  and  are 
more  tightly  packed  together.  The  increased  affinity  for  dye- 
stuffs  exhibited  by  mercerized  cotton  is  not  to  be  considered  a 
new  inherent  property  of  the  modified  cellulose  induced  by  a 
change  in  its  chemical  composition.  It  is  no  doubt  a  result  of 
the  modified  physical  structure  of  the  fibre  itself;  that  is,  when 
the  cell  elements  have  become  distended,  like  a  sponge  they  have  a 
greater  power  of  absorption  and  retention  of  liquids  than  when 
in  a  flattened  and  collapsed  condition. 

The  high  lustre  imparted  to  the  cotton  by  mercerizing  is  brought 
about  by  other  conditions  than  the  mere  action  of  the  caustic 
alkali.*  /  In  the  swelling  of  the  cell-walls  and  consequent  con- 
traction of  the  fibre,  the  surface  remains  wrinkled  and  uneven, 
due  to  the  unequal  strain  of  expansion.  If,  howrever,  the  ends  of 
the  fibre  are  fixed,  and  thus  prevented  from  contracting  when 
subjected  to  the  chemical  action  of  the  alkali,  the  swelling  of  the 
cell-walls  will  cause  the  surface  to  become  smooth  and  even,  and 
capable  of  reflecting  light  with  but  little  scattering  of  the  rays, 
similar  to  a  polished  surface.  Another  condition  which  also 
has  much  to  do  with  the  production  of  the  lustrous  appearance 
is  no  doubt  to  be  found  in  the  physical  modification  of  the  cell 
elements  themselves.  When  the  fibre  swells  up  under  the  action 
of  the  caustic  alkali,  its  substance  becomes  gelatinous  and  trans- 
lucent, and  this  has  a  marked  effect  on  the  optical  properties  of 
the  fibre,  and  enhances  the  lustre  considerably  by  lessening  the 
proportion  of  light  absorbed.f 

*  It  has  been  claimed  that  the  mercerizing  effect  may  be  obtained  without 
tension  by  the  addition  of  glucose  to  the  alkaline  bath.  The  addition  of  other 
substances,  such  as  ether,  aluminium  chloride,  etc.,  have  been  claimed  to  pro- 
duce the  same  result.  But  it  is  to  be  doubted  whether  a  high  lustre  is  obtained, 
by  any  of  these  methods. 

f  Dr.  Frankel  has  advanced  the  opinion  that  the  high  lustre  exhibited  by 
mercerized  cotton  is  mainly  due  to  the  fibre  having  lost  its  thin  cuticle  during 
the  process.  But  this  theory  is  overthrown  by  the  fact  that  if  mercerized  cotton 


160  THE   TEXTILE  FIBRES. 

Considerable  difference  is  to  be  observed  in  the  strength 
and  elasticity  of  cotton  mercerized  without  tension  and  that 
mercerized  with  tension.  Buntrock,  in  a  research  on  this  point, 
found  that  cotton  yarn  mercerized  without  tension  showed  an 
increase  of  68  per  cent,  in  its  tensile  strength,*  whereas  the  same 
cotton  mercerized  under  tension  gave  an  increase  of  only  35 
per  cent.  With  respect  to  the  elasticity  of  the  yarn,  the  same 
chemist  ascertained  that  the  untreated  cotton  employed  in  his 
experiments  stretched  1 1  per  cent,  of  its  length  before  breaking;  the 
amount  for  cotton  mercerized  without  tension  was  17  per  cent.,  an 
increase  of  54  per  cent.;  cotton  mercerized  under  tension  showed 
no  increase  in  elasticity  at  all,  and  could  only  be  stretched  the 
original  n  per  cent,  before  breaking.  These  figures,  of  course, 
are  not  absolute  for  all  varieties  of  cotton,  but  will  vary  within 
considerable  limits,  depending  upon  the  character  of  the  raw 
cotton  employed.  Attention  must  also  be  drawn  to  the  fact 
that  the  figures  for  the  tensile  strength  and  elasticity  quoted  above 
were  obtained  by  using  spun  yarn  and  are  not  based  on  the  single 
fibre.  Of  course  it  is  the  strength  of  the  yarn  which  is  desired  in 
practice,  but  the  figure  for  this  is  not  necessarily  that  for  the  fibre 
itself.  In  mercerizing  yarn  or  cloth,  it  must  be  borne  in  mind 
that  the  fibres  shrink  considerably,  and  in  doing  so  become  more 
closely  knit  together;  therefore  the  increase  in  tensile  strength,  as 
ascertained  by  Buntrock,  represents  really  the  greater  coherence  of 
the  fibres  to  one  another,  rather  than  an  increase  in  the  strength 
of  the  individual  fibre,  because  in  breaking  a  yarn  spun  from  a 
larire  number  of  fibres  there  is  little  or  no  actual  breaking  of  the 
films  themselves,  but  only  a  pulling  apart  of  the  latter.  The 
same  criticism  also  applies  to  a  determination  of  the  elasticity. 
It  would,  perhaps,  be  more  scientific  to  determine  the  breaking 

is  again  subjected   t<>  the  action  of  rold  strong  caustic  soda  it  contracts  nearly 
as  much  as  raw  cotton  would  do,  and  IOM-S  its  silky  lustre  entirely. 

*  (irosheintz  gives  the  following  results  of  some  experiments  on  the  effect  of 
merrcri/ation  on  the-  tensile  .-trength  of  cotton,  rnnieneri/ed  yarn  broke  with  a 
load  of  356-360  grams;  same-  yarn  men  cri/cd  in  (  old  aqueous  <  austic  soda  (35°  B.) 
broke-  with  530-570  grams;  same  yarn  men  eri/cd  \\ith  cold  alcoholic  caustic 
s«.d -i  10  per  cent.)  broke  with  600-645  grams;  same  (except  that  hot  alcoholic 
caustii  -<x\:\.  was  used;  broke  with  a  load  of  690-740  grams. 


MERCERIZED   COTTON.  161 

strain  and  elasticity  of  the  separate  fibres  rather  than  that  of  the 
yarn  or  cloth;  but  it  may  be  assumed,  with  considerable  show 
of  reason,  that  these  figures  of  Buntrock  will  represent  a  fair 
relation  between  the  strength  and  elasticity  of  the  individual 
fibres.  The  cause  of  the  lesser  increase  in  tensile  strength  of 
cotton  mercerized  under  tension  as  compared  with  that  of  the 
same  cotton  mercerized  without  tension  is  to  be  attributed  to  the 
fact  that  when  the  shrinkage  of  the  fibre  is  prevented  by  the 
application  of  an  external  force,  the  cell  tissues  cannot  become 
as  compact  as  otherwise,  and  there  is  also  an  internal  strain 
induced  which  lessens  the  ultimate  strength  of  the  fibre.  This 
latter  condition  also  accounts  for  the  lack  of  any  increase  in 
the  elasticity  of  the  mercerized  fibre;  the  fibre  when  mercerized 
under  tension  is  already  in  a  stretched  or  strained  condition,  and 
can  hardly  be  expected  to  give  the  same  degree  of  elasticity  as 
if  tension  had  not  been  applied. 

2.  Conditions  of  Mercerizing. — The  proper  conditions  for 
carrying  into  practical  operation  the  mercerizing  process  are 
simple  and  easily  realized.  Caustic  soda  is  the  most  suitable 
and  convenient  reagent  *  for  bringing  about  the  hydration  of 
the  cellulose;  and  it  has  been  found  that  a  solution  of  density 
between  60°  and  yc°  Tw.  gives  the  best  results.  Caustic  soda 
solutions  of  less  density  than  15°  Tw.  have  scarcely  any  action  on 
cotton;  the  maximum  effect  appears  to  be  produced  by  a  con- 
cen  ration  of  about  60°  Tw.,  though  the  difference  between  this 
and  that  obtained  at  50°  Tw.  is  not  very  marked,  and  even  at 
40°  Tw.  the  mercerizing  action  of  the  alkali  is  quite  strong.  Other 
reagents,  however,  than  caustic  alkalies,  may  be  employed  for 
the  hydrolysis  of  the  cotton.  Concentrated  mineral  acids,  such, 
for  instance,  as  sulphuric  acid  at  a  density  of  100°  to  125°  Tw., 
will  bring  about  the  mercerizing  effect  more  or  less  perfectly: 
the  same  is  also  true  of  certain  metallic  salts,  most  notably  the 
chlorides  of  zinc,  calcium,  and  tin.  Beyond  a  mere  theoretical 

*  Solutions  of  caustic  potash  probably  give  a  somewhat  better  lustre,  and 
the  shrinkage  of  the  fibre  is  less  than  with  caustic  soda.  But  these  small  ad- 
vantages are  not  sufficient  to  compensate  for  the  extra  expense  which  would  be 
entailed  by  the  use  of  caustic  potash. 


162  THE   TEXTILE  FIBRES. 

and  chemical  interest,  however,  mercerizing  by  means  of  such 
reagents  has  no  practical  value.*  The  addition  of  various  chem- 
icals, however,  has  been  made  to  the  caustic  alkali  solution  with 
beneficial  results.  It  has  been  observed,  for  instance,  that  the 
addition  of  zinc  oxide  has  a  very  marked  effect,  and  probably  is  of 
considerable  value  in  the  practical  working  of  the  process.  The 
addition  of  glycerin,  though  perhaps  of  some  benefit  in  assisting 
in  the  even  and  thorough  penetration  of  the  liquor  into  the  fibre, 
can  hardly  be  said  to  appreciably  modify  the  general  operation  of 
the  alkali. f  Previous  treatment  with  Turkey- red  oil  is  also  of 
benefit  for  the  same  reason;  this  is  also  true  of  such  substances 
as  sodium  silicate,  sodium  aluminate,  and  soap. 

The  temperature  at  which  the  reaction  is  carried  out  should 
not  be  higher  than  the  usual  atmospheric  degree;  in  fact,  it  has 
been  recommended  to  lower  the  temperature  of  the  caustic  soda 
solution  by  the  addition  of  ice,  but  this  procedure  does  not  appear 
to  add  anything  of  material  advantage.  At  elevated  temperatures 
caustic  soda  appears  to  exert  a  destructive  effect  on  cotton,  prob- 
ably due  to  the  formation  of  oxycellulose  through  hydrolysis  and 
subsequent  oxidation.  Beyond  a  certain  temperature  the  mer- 
cerizing effect  rapidly  diminishes,  and  at  the  boil  it  is  scarcely 
appreciable.!  The  best  results  appear  to  be  obtained  when  the 

*  The  use  of  sulphide  of  sodium  or  potassium  instead  of  caustic  alkali  has 
been  proposed;  but  the  process  yields  very  uncertain  results.  It  is  claimed  that 
by  adding  ether  to  the  caustic  soda  solution  good  mercerization  can  be  obtained 
with  but  little  contraction  of  the  fibre,  but  as  this  process  requires  fifty  parts  of 
ether  to  twenty  parts  of  caustic  soda  solution,  the  expense  renders  it  ridiculously 
impracticable.  It  is  said  that  the  addition  of  carbon  bisulphide  to  the  bath  of 
caustic  soda  very  materially  increases  the  lustre;  this  causes  a  disintegration  of 
the  fibre,  however,  through  the  formation  of  viscose  (see  p.  153);  hence  the 
treatment  should  be  very  brief,  otherwise  the  cotton  will  be  seriously  tendered. 
The  mercerized  fibre  at  first  is  as  stiff  as  horse-hair,  but  this  effect  can  be  removed 
by  repeated  washing.  The  sulphur  can  be  removed  from  the  cotton  by  washing 
in  a  solution  of  sal-ammoniac,  and  this  should  be  done  before  the  material  is  treated 
with  an  acid  bath,  as  the  latter  would  cause  a  precipitation  of  sulphur  on  the 
fibre  and  so  spoil  the  lustre. 

f  In  the  practical  manipulation  of  the  mercerizing  process  it  has  been  found 
that  the  impregnation  with  caustic  liquor  is  greatly  facilitated  by  the  addition  of 
5  per  cent,  of  alcohol  on  the  weight  of  the  caustic  soda. 

%  Beltzer,  however,  claims  that  caustic  soda  solutions  of  65°  Tw.  gave  the 
same  results  in  mercerizing  at  90°  C.  as  at  15°  C.,  but  the  cotton  mercerized  at 


MERCERIZED  COTTON.  163 

temperature  is  maintained  at  20°  C.,  or  lower.  Above  this  point 
the  contraction  of  the  fibre  (which  may  be  taken  as  a  measure  of 
the  degree  of  mercerization)  grows  less  and  less  with  rise  of  tem- 
perature. 

The  mercerizing  action  of  caustic  soda  is  rather  a  rapid  one, 
as  it  requires  only  a  few  minutes  for  its  completion;  in  fact,  it 
appears  to  take  place  simultaneously  with  the  impregnation  of 
the  fibre  by  the  liquid.  In  ten  minutes  mercerization  is  prac- 
tically complete,  and  lengthening  of  the  time  does  not  increase 
the  mercerizing  effect;  in  fact,  too  long  a  contact  of  the  cotton 
with  the  caustic  alkali  is  to  be  avoided,  especially  if  the  impreg- 
nated fibre  is  exposed  to  the  air,  as  there  is  danger  of  a  breaking 
down  of  the  cellular  structure  and  a  consequent  deterioration  in 
the  strength  of  the  fibre.  The  time  of  immersion  also  appears 
to  be  independent  of  both  the  temperature  and  the  concentration 
of  the  alkali. 

There  are  two  ways  in  which  the  tension  may  be  applied  in 
mercerizing:  (a)  The  material  may  be  held  in  a  state  of  tension 
during  the  time  of  its  treatment  with  the  caustic  alkali,  and  until 
the  alkali  has  been  washed  out,  in  which  case  the  tension  should 
be  so  maintained  that  the  material  cannot  shrink;  (b)  the  ten- 
sion may  be  applied  after  the  material  has  been  treated  with  the 
caustic  alkali,  but  before  the  latter  is  washed  out,  in  which  case 
sufficient  tension  should  be  exerted  to  stretch  the  material  back 
to  its  original  length.  If  the  tension  is  not  applied  until  after  the 
alkali  has  been  removed  from  the  fibre,  no  lustring  effect  is  pro- 
duced, it  is  absolutely  essential  that  the  stretching  should  take 
place  while  the  fibre  is  in  the  form  of  an  alkali-cellulose,  and 
before  it  has  been  converted  by  treatment  with  water  into  hydrated 
cellulose. 

According  to  the  experiments  of  Herbig,  the  stretching  force 
necessary  to  keep  the  cotton  in  its  original  length  during  mercer- 
ization is  only  from  a  quarter  to  a  third  of  that  necessary  to  do 

the  higher  temperature  was  much  more  transparent  than  the  other.  The  lustre, 
however,  was  in  no  wise  inferior.  If  the  mercerization  be  conducted  at  90°  C. 
it  is  necessary  to  keep  the  cotton  entirely  immersed,  to  guard  it  from  contact 
with  the  air,  otherwise  it  will  become  seriously  weakened. 


1 64  THE   TEXTILE  FIBRES. 

the  stretching  after  mercerization ;  but  there  appears  to  be  no 
appreciable  difference  in  the  lustre  obtained.  It  would  appear, 
however,  that  stretching  beyond  a  certain  point  ceases  to  increase 
the  lustre,  and  to  obtain  the  maximum  lustring  effect  it  is  not 
necessary -to  stretch  the  cotton  back  to  its  original  length.  Her 
big  concluded  that  stretching  during  mercerization  is  disadvan- 
tageous, and  it  is  best  to  mercerize  the  yarn  loose,  wring  it,  and 
only  stretch  while  rinsing,  as  the  required  stretching  force  is 
then  quite  small.  The  best  time  for  stretching,  then,  is  during 
the  conversion  of  the  soda- cellulose  into  the  hydrocellulose.  If 
the  stretching  does  not  take  place  until  after  rinsing,  almost 
twice  the  force  is  necessary  to  restore  the  yarn  to  its  original 
length,  as  when  in  contact  with  the  lye,  and  the  lustre  is  decidedly 
inferior.  The  stretching  force  also  appears  to  depend  on  the 
twist,  being  greater  in  proportion  as  the  twist  is  harder.* 

*  Herbig  gives  a  summary  of  his  experimental  results  as  follows: 

1.  Loose   yarn   mercerized   without   any   stretching,   whether   long-  or   short- 
stapled,  and  whether  with  or  without  a  hard  twist,  has  less  lustre  than  unmer- 
cerized  yarn.     But  even  with  a  very  slight  tension  the  lustre  is  greater. 

2.  Both  with  long-  and  short -stapled  cotton  the  lustre  only  becomes  marked 
when  the  stretching  force  is  sufficient  to  bring  the  yarn  back  to  its  original  length. 

3.  Stretching  beyond  the  original  length  does  not  give  any  increase  in  lustre. 

4.  Considerable  difference  is  observable  in  the  stretching  force  needed  between 
loose  mercerization  followed  by  stretching  in  the  lye,  and  keeping  the  cotton  at 
its  original  length  during  mercerization,  as  in  the  latter  case  only  one-third  to 
one-quarter  of  the  force  is  necessary  to  produce  the  silky  lustre. 

5.  The  stretching  of  the  yarn  requires  only  a  small  force  when  mercerized 
loose  and  if  applied  when  rinsing  is  actually  in  progress;  for  the  best  time  for 
stretching  is  during  the  conversion  of  the  soda-cellulose  into  hydrocellulose. 

6.  When  rinsing  is  over,  twice  as  much  force  is  needed  to  restore  the  original 
length  as  is  required  for  yarn  still  in  contact  with  the  lye;    and  yarns  so  treated 
contract  somewhat  on  drying,  and  exhibit  an  inferior  lustre. 

7.  The  stretching  force  necessary  in  mercerizing  yarn  varies  with  the  twist, 
and  in  general  is  greater  in  proportion  as  the  twist  is  harder. 

8.  The  production  of  the  silky  lustre  does  not  depend  primarily  on  the  amount 
of  force  employed  in  stretching,  as  soft  yarn  with  only  a  small  amount  of  twist 
can  be  lustred. 

9.  The  production  of  the  silky  lustre  is  independent  of  the  cotton  being  long- 
or  short-stapled,  as  short-stapled  American  cotton  with  even  a  loose  twist  <  an 
be  given  a  silky  lustre. 

10.  The  production  of  a  high  degree  of  lustre  depends  to  a  considerable  extent 
on  the  fineness  of  the  fibre,  and  its  natural  lustre.     This  is  apparent  in  mercerizing 
sea  island  and  Egyptian  cotton. 


MERCERIZED   COTTON.  165 

By  the  washing  of  the  material  after  steeping  in  caustic  alkali, 
a  twofold  object  is  gained.  In  the  first  place,  the  action  of  the 
water  on  the  alkali- cellulose  is  to  effect  a  chemical  transforma- 
tion into  cellulose  hydrate,  and  this  action  is  as  really  essential 
to  mercerizing  as  the  action  of  the  caustic  soda  itself.  In  the 
second  place,  the  washing  is  conducted  for  the  purpose  of  remov- 
ing all  excess  of  caustic  alkali  from  the  material.*  Caustic  soda 
is  held  quite  tenaciously  by  cotton,  and  it  requires  a  very  thorough 
and  long-continued  washing  to  remove  the  last  traces  of  this 
compound.  In  order  to  shorten  the  period  required  for  washing, 
it  is  customary  to  give  the  cotton  first  a  rinsing  in  fresh  water, 
after  which  the  tension  may  be  relieved,  and  then  to  wash  with 
acidulated  water,  using  acetic  acid  for  this  purpose.!  On  dry- 
ing the  material  without  further  washing,  it  will  be  found  that 
the  acetic  acid  has  imparted  to  the  cotton  a  certain  degree  of 
*  *  scroop ' '  somewhat  after  the  nature  of  silk,  without  in  any  man- 
ner tendering  the  fibre.  If  other  acids,  and  especially  mineral 
acids,  are  employed  for  washing,  a  subsequent  rinsing  with  fresh 
water  and  soaping  is  necessary  for  the  purpose  of  neutralizing 
all  of  the  acid,  which  would  otherwise  seriously  tender  the  goods 
on  drying  unless  the  amount  of  acid  employed  is  so  accurately 
adjusted  as  not  to  leave  any  free  acid  in  the  fibre. 

The  character  of  the  fibre  employed  has  a  considerable  influ- 
ence on  the  success  of  the  mercerizing  process.  From  the  very 
nature  of  the  fact  that  a  considerable  degree  of  tension  must  be 
applied  to  the  fibre  during  the  process  in  order  to  obtain  the 
desired  lustre,  it  would  be  natural  to  expect  that  the  longer  the 
staple  of  the  fibre  the  more  readily  would  it  lend  itself  to  the 
requirements  of  the  operation.  And  such,  indeed,  is  found  to 
be  the  case;  the  long-stapled  sea- island  %  and  Egyptian  varieties 

*  When  mercerized  cotton  is  rinsed  with  ammonia  instead  of  water  it  retains 
its  gelatinous,  parchment-like  consistency  throughout  the  rinsing,  and  can  be 
stretched  to  its  original  length  without  breaking.  If  the  cotton  is  then  rinsed  with 
water  while  still  stretched,  the  fibre  regains  its  original  appearance,  and  acquires 
a  lustre  as  good  as  that  obtained  in  the  usual  way. 

f  Sulphuric  acid  is  much  used  in  the  washing.  The  acid  employed  is  of  £°  B. 
strength,  and  at  a  temperature  of  50°  C. 

J  The  preparation  by  combing  of  cotton  for  mercerization  has  a  considerable 


1 66  THE    TEXTILE  FIBRES. 

of  cotton  are  those  especially  adapted  for  use  in  the  preparation 
of  mercerized  cotton,  while  the  shorter- stapled  varieties  are  but 
little  employed  for  this  purpose,  as  the  lustre  obtained  with  them 
is  by  no  means  as  pronounced.*  The  quality  of  being  mercerized, 
however,  is  not  an  inherent  property  of  any  special  variety  of 
cotton,  as  was  formerly  supposed  to  be  the  case;  any  variety  of 
cotton  is  capable  of  mercerization,  the  only  essential  being  that 
the  fibre  shall  be  maintained  in  a  state  of  tension.  In  order  that 
this  condition  be  realized  with  short-stapled  fibres,  the  yarn 
operated  upon  must  be  tightly  twisted  in  order  to  present  suffi- 
cient cohesion  among  the  individual  fibres  to  allow  of  the  high 
tension  required;  this,  on  the  other  hand,  prevents  an  even  and 
thorough  penetration  of  the  caustic  alkali  into  the  substance  of 
the  fibre,  so  that,  on  the  whole,  the  results  obtained  with  short- 
stapled  fibres  are  not  at  all  comparable  with  the  long- stapled 
varieties.f  By  later  improvements  in  the  manner  of  applying 

influence  on  the  subsequent  lustre  of  the  yarn.  Sea-island  cotton  possesses  a 
rather  silky  fibre  to  begin  with,  and  this  is  made  more  adaptable  to  the  production 
of  a  high  lustre  by  combing,  in  which  operation  the  fibres  are  arranged  parallel, 
and  still  further  by  gassing,  which  burns  off  the  minute  outer  hairs.  Yarns  possess- 
ing considerable  lustre  were  made  in  this  manner  with  fine  counts  of  sea-island 
cotton  long  before  the  discovery  of  lustring  by  mercerization,  and  it  was  always 
recognized  that  the  parallelism  of  the  fibres  so  obtained  by  combing  (and  some- 
times a  second  combing)  was  a  great  factor  in  the  production  of  a  silky  and 
lustrous  yarn. 

*  Fabrics  of  vegetable  fibres  (cotton  or  linen)  may  also  be  mercerized  in 
patterns  by  printing  on  certain  compounds  capable  of  resisting  the  action  of  the 
caustic  soda  in  the  subsequent  mercerizing  process.  Resists  suitable  for  this 
purpose  are,  in  the  first  place,  organic  compounds  which  readily  coagulate,  such 
as  albumin  and  casein;  and  secondly,  such  salts,  acids,  or  oxides  which  may 
act  by  neutralizing  the  caustic  alkali,  or  from  which  a  hydrate  may  be  precipi- 
tated on  the  fabric  by  its  action.  Such  compounds,  for  instance,  as  the  salts  of 
aluminium  or  zinc,  organic  acids,  and  the  oxides  of  zinc,  aluminium,  or  chromium 
are  quite  suitable.  Very  beautiful  effects  are  said  to  be  obtainable  by  this 
process. 

t  Boucart  gives  the  following  reasons  why  only  long-stapled  cotton,  and  that 
only  in  particular  counts,  gives  good  results  on  mercerization.  A  simple  thread 
consists  of  a  sort  of  twisted  wick  composed  of  nearly  parallel  fibres.  The  twist 
depends,  as  regards  the  angles  it  makes  with  the  length  of  the  thread,  both  upon 
the  kind  of  cotton  and  upon  the  count  of  the  yarn.  Of  the  two  sorts  of  simple 
yarns,  warp-yarns  have  more  cohesion  among  their  elements  than  tensile  strength, 
while  the  reverse  is  the  case  with  weft-yarns.  The  result  is  that  under  gradually 

0 


MERCERIZED  COTTON.  167 

the  tension,  however,  it  would  seem  that,  by  realizing  the  proper 
mechanical  conditions,  even  cotton  of  comparatively  short  staple 
will  be  capable  of  being  mercerized  in  a  more  successful  man- 
ner than  heretofore.* 

3.  Properties  of  Mercerized  Cotton. — Outside  of  its  high 
lustre  and  somewhat  increased  tensile  strength,  mercerized  cotton 
exhibits  but  few  apparent  differences  from  the  ordinary  fibre.. 
Towards  dyestuffs  and  mordants  it  is  rather  more  reactive,  and 

increasing  tension  weft-fibres  slide  past  one  another  without  breaking,  but  warp- 
fibres  break  before  any  such  occurrence  takes  place.  The  degree  of  twist  also 
depends  on  the  mean  staple,  and  the  angle  between  the  thread  and  the  axis  at 
any  point  is  proportional  to  the  length  of  the  thread.  The  degree  of  twist  which 
is  required  to  make  the  cohesion  exceed  the  tensile  strength  depends  naturally 
on  the  strength  of  the  fibre.  The  mercerizing  process  tends  to  shorten  each 
individual  fibre,  and  this  shortening  is  resisted  by  tension  in  the  direction  parallel 
to  the  axis  of  the  thread.  Hence  the  greater  the  angle  the  thread  makes  with 
that  axis  the  less  is  the  effect  of  the  tension,  and  if  any  portion  of  the  fibre  is  at 
right  angles  to  the  axis  it  is  not  affected  by  the  tension  at  all.  Hence  a  simple  warp 
thread  can  only  receive  a  medium  amount  of  gloss  from  mercerization,  and  the 
less  the  greater  the  twist.  Slightly  twisted  threads  must  give  the  best  lustre,  but 
if  the  cohesion  of  the  fibres  is  less  than  the  contractile  force  exerted  by  the  lye, 
the  fibres  slip  past  each  other  and  no  lustre  is  produced.  But  if  the  weft-threads 
are  fixed,  as  in  piece  goods,  they  take  a  better  lustre  than  the  warp,  although  the 
latter  is  usually  made  of  better  cotton.  Short-stapled  cotton  lustres  badly  because 
it  must  be  more  tightly  twisted.  The  best  lustre  of  all  is  obtained  with  twofold 
twist,  in  which  the  outer  fibres  lie  parallel  to  the  axis,  and  the  yarn  should  be 
well  singed  to  remove  projecting  threads. 

*  The  process  of  mercerizing  has  been  subject  of  late  to  a  great  number  of 
patents,  especially  by  Thomas  and  Prevost  of  Germany.  This  has  resulted  in 
considerable  litigation  in  many  countries.  As  far  as  the  actual  chemical  process 
itself  is  concerned,  however,  there  does  not  appear  to  have  been  any  material 
advance  beyond  the  facts  first  discovered  by  Mercer  and  patented  by  him  in  1850; 
with  regard  to  the  element  of  carrying  out  the  process  under  tension,  it  may  be 
said  that  this  was  first  described  and  patented  by  Arthur  Lowe  in  1890,  and  this 
included  the  application  of  tension  either  during  or  after  the  treatment  with  caustic 
alkali.  Lowe's  object  in  stretching  the  material,  however,  was  primarily  to  pre- 
vent the  loss  encountered  by  the  shrinkage  of  the  goods,  though  he  does  also  make 
a  specific  statement  that  the  cotton  acquires  an  increased  lustre  and  finish  by 
the  process.  The  only  novelty  put  forward  by  Thomas  and  Prevost  was  the  use 
of  a  particular  kind  of  cotton,  that  is,  long-stapled  varieties;  but  as  both  Mercer's 
and  Lowe's  patents  claim  the  use  of  all  varieties  of  cotton,  it  is  difficult  to  see 
on  what  ground  Thomas  and  Prevost  can  substantiate  their  claim  for  a  patent. 
Patents  covering  the  process  of  mercerizing  appear  to  be  without  foundation; 
though  for  machinery  and  appliances  for  carrying  out  the  same  such  patents 
may  be  perfectly  legitimate. 


1 68  THE   TEXTILE  FIBRES. 

consequently  will  dye  deeper  shades  with  the-  same  amount  of 
dyestuff  than  ordinary  cotton ;  this  property  is  rather  to  be  ascribed 
to  the  increased  absorptivity  of  the  fibre  than  as  the  result  of  any 
chemical  modification  of  the  cellulose  composing  it;  it  is  also 
independent  of  the  method  of  mercerizing,  that  is,  whether  accom- 
panied by  tension  or  not. 

Microscopically  the  mercerized  cotton  fibre  exhibits  a  con- 
siderable difference  from  that  of  ordinary  cotton.  Whereas  the 
latter  when  viewed  under  the  microscope  appears  as  a  twisted 
flat  band  with  thickened  edges,  and  in  cross-section  like  a  col- 
lapsed tube,  mercerized  cotton  appears  as  a  smooth  rounded 
cylindrical  fibre,  the  cross-section  of  which  is  more  or  less  cir- 
cular. It  rarely  happens  that  a  fibre  absolutely  loses  all  of  its 
twist,  though  the  degree  of  mercerization  may  be  measured  by 
the  freedom  of  the  fibre  from  irregularities  and  twists.  Under 
ordinary  conditions  when  the  cotton  is  mercerized  in  a  state  of 
tension,  it  will  also  be  found  that  many  fibres  will  remain  in 
their  original  form,  or  unmercerized,  whereas  others  will  be 
mercerized  only  in  portions  of  their  length.  The  microscopical 
examination  of  mercerized  cotton  is  important  in  determining 
just  how  perfectly  the  process  has  been  carried  out,  which  may  be 
judged  by  the  relative  number  of  unmercerized  or  partially  mer- 
cerized fibres  which  may  be  present. 

Cotton  may  be  mercerized  either  in  the  form  of  yarn  or  of 
cloth,  and  it  is  principally  done  in  the  unbleached  condition. 
There  has  been  some  dispute  as  to  which  is  best :  to  mercerize  first 
and  bleach,  or  to  bleach  first  and  then  mercerize;  experience, 
however,  appears  to  favor  the  first  method.  In  the  bleaching 
operations,  which  usually  involve  a  rather  severe  treatment  of  the 
cotton  first  with  moderately  strong  alkalies  and  subsequently 
with  solutions  of  bleaching  powder,  the  fibre  suffers  more  or  less 
chemical  alteration  so  that  in  the  mercerizing  process  it  can  no 
longer  enter  into  chemical  union  with  the  caustic  soda  employed; 
and  hence  true  mercerization  is  not  effected.  Although  cotton 
should  be  thoroughly  scoured  ("boiled  out")  before  being  mer- 
u-ri/i-d,  it  is  best  not  to  use  alkalies  for  the  purpose,  but  to  employ 
Turkey-red  oil  (or  other  ^uitabk-  sulphated  oil)  or  soap.  If 


MERCERIZED   COTTON.  169 

bleaching  is  carefully  conducted  after  mercerizing,  the  injury  to 
the  lustre  of  the  fibre  is  very  slight.  Mercerized  cotton  does  not 
require  a  prolonged  boiling  in  alkalies  previous  to  the  operation 
of  bleaching  as  with  ordinary  cotton.  To  obtain  the  best  condi- 
tions for  high  lustre  yarn  should  be  well  "gassed"  (singed)  before 
mercerizing,  as  othenvise  the  external,  hairy  fibres  remain  loose 
and  cannot  be  subjected  to  tension.  As  a  result  these  fibres 
shrink,  and,  remaining  without  lustre  themselves,  hide  to  a  cer- 
tain extent  the  lustred  surface  of  the  yarn.  Moreover,  caustic 
soda  has  a  felting  action  on  these  free  filaments,  and  felting  is 
especially  harmful  to  lustre. 

In  mercerizing  cloth  the  action  taking  place  between  the 
sizing  materials  (always  present  to  a  greater  or  lesser  degree  in 
cotton  cloth)  and  the  caustic  alkali  is  sufficient  at  times  to  raise 
the  temperature  considerably,  which  may  result  in  a  deficient 
lustre.  In  such  cases  recourse  must  be  had  to  artificial  cooling 
by  addition  of  ice  or  a  current  of  cold  water  in  order  to  prevent 
an  undue  rise  in  temperature. 

When  mercerized  cotton  is  to  be  bleached,  it  is  best,  after  the 
first  rinsing,  to  remove  the  major  portion  of  the  caustic  soda  and 
arrest  the  mercerization,  not  to  rinse  again  in  acidulated  water,  as 
would  ordinarily  be  done  if  the  material  were  not  to  be  immedi- 
ately bleached.  The  small  amount  of  caustic  soda  which  still 
remains  in  the  cotton  acts  in  a  beneficial  manner  in  bleaching. 

A  silky  lustre  resembling  that  produced  by  mercerization  can 
be  given  to  cotton  cloth  by  means  of  what  is  known  as  a  calender 
finish.  This  is  accomplished  by  passing  the  cloth  between  rollers 
under  heavy  pressure,  one  of  the  rollers  being  engraved  with 
obliquely  set  lines  ruled  from  125  to  600  to  the  inch.  The  effect 
is  to  produce  a  large  number  of  parallel,  flat  surfaces  on  the  cloth, 
which  causes  it  to  acquire  a  high  lustre.  By  conducting  the  oper- 
ation with  hot  rollers  quite  a  permanent  finish  can  be  produced 
which  closely  approximates  mercerized  cotton.  Cloth  so  fin- 
ished, however,  loses  its  lustre  in  a  large  degree  on  washing. 
The  method  is  chiefly  known  as  the  "  Schreiner  process." 


CHAPTER  XIII. 

ARTIFICIAL  SILKS;   LUSTRA-CELLULOSE. 

OWING  to  the  high  price  and  value  of  silk  as  a  textile  fibre, 
there  have  been  numerous  attempts  made  to  produce  an  artificial 
filament  resembling  it  in  properties.  Several  of  these  processes 
have  been  attended  with  a  considerable  degree  of  success,  and 
at  the  present  time  artificial  silk  has  become  a  commercial  article, 
and  is  used  in  considerable  quantity  by  the  textile  trade.  The 
varieties  of  these  silks  divide  themselves  into  the  following  classes: 

(1)  Pyroxylin  silks,  made  from  a  solution  of  guncotton  in  a 
mixture  of  alcohol  and  ether. 

(2)  Fibres  made  from  a  solution  of  cellulose  in  ammoniacal 
copper  oxide  or  chloride  of  zinc. 

(3)  Viscose  silk,  made  from  a  solution  of  cellulose  thiocarbon- 
ate. 

(4)  Gelatin   silk,    made   from   filaments   of  gelatin   rendered 
insoluble  by  treatment  with  formaldehyde. 

With  the  exception  of  the  last  class,  all  of  these  so-called  silks 
are  filaments  of  cellulose,  resolidified  from  various  forms  of  solu- 
tions, hence  it  has  been  proposed  to  give  these  fibres  the  general 
name  of  lustra-cellulose,  as  one  more  descriptive  of  their  true 
nature. 

The  large  majority  of  the  lustra-cellulose  used  in  trade  at  the 
present  time  falls  under  the  first  class  of  pyroxylin  silks.  This 
represents  the  oldest  and  most  successful  method  employed  for 
the  manufacture  of  this  interesting  fibre;  and  there  are  three 
chief  processes  by  which  the  silk  is  made,  known  by  the  names 
of  the  respective  inventors:  Chardonnet,  du  Vivier,  and  Lehner. 
All  of  these  processes  use  a  solution  of  nitrocellulose  as  a  base, 

170 


ARTIFICIAL  SILKS;  LUSTRA-CELLULOSE.  171 

and  employ  the  same  general  mechanical  idea  to  produce  the 
filament  or  fibre,  the  principle  being  to  force  a  solution  of 
nitrocellulose  through  a  fine  capillary  tube,  coagulate  the  thin 
stream  of  solution  thus  obtained,  and  finally  denitrate  and  reel 
the  thread  or  filament  so  obtained.  As  described  on  p.  150, 
cellulose,  on  treatment  with  nitric  acid,  can  be  made  to  yield  a 
series  of  nitrocelluloses,  the  exact  compound  obtained  being 
dependent  upon  the  conditions  of  treatment. 

Chardonnet  silk  is  prepared  from  octonitrocellulose,  dissolved 
in  a  mixture  of  alcohol  and  ether.  The  solution  is  coagulated 
by  passage  through  water,  and  is  subsequently  denitrated  * 
by  a  treatment  with  dilute  nitric  acid,  chloride  of  iron,  and  am- 
monium phosphate.  It  forms  a  glossy,  flexible  fibre,  possessing 
the  peculiar  "feel"  and  "scroop"  of  true  silk. 

The  basis  of  du  Vivier's  silk  is  a  solution  of  trinitrocellulose 
in  glacial  acetic  acid.  In  practice,  this  is  mixed  with  a  solution  of 
gutta-percha  in  carbon  disulphide,  and  one  of  isinglass  in  glacial 
acetic  acid.  Small  quantities  of  glycerin  and  castor-oil  are 
added,  and  the  mixture  is  drawn  through  the  spinning- tubes  into 
water,  where  it  becomes  coagulated.  The  thread  which  is  so 
formed  is  treated  successively  with  soda,  albumin,  mercuric 
chloride,  and  carbon  dioxide.  Du  Vivier's  silk  is  hard,  and  very 
white  and  glossy. 

Lehner  employs  a  solution  of  nitrocellulose  in  ether  and 
methyl  alcohol,  to  which  he  adds  a  solution  of  natural  silk  in 
glacial  acetic  acid.  The  thread  is  coagulated  by  passage  through 
a  mixture  of  turpentine,  chloroform,  and  juniper-oil,  and  is  after- 
wards treated  with  a  solution  of  sodium  acetate,  f 

*  When  first  prepared,  pyroxylin  silks  were  very  inflammable,  which  led  to 
their  being  regarded  with  disfavor.  The  processes  of  denitration,  however,  have 
now  rendered  them  even  less  inflammable  than  ordinary  cotton.  Antiphlogin  is  the 
trade-name  of  a  mixture  for  the  purpose  of  overcoming  the  inflammable  nature 
of  artificial  silk.  It  consists  of  boric  acid,  phosphate  of  ammonia,  and  acetic 
acid.  Pyroxylin  steeped  in  this  solution  is  said  to  be  incombustible. 

f  The  manufacture  of  artificial  silk  has  of  late  years  become  an  enterprise 
of  commercial  importance.  There  are  factories  producing  pyroxylin  silk 
at  Besancon  (France),  Spreitenbach  and  Zurich  (Switzerland),  Wobton  (Eng- 
land), and  Elberfeld  (Germany).  The  fibres  are  formed  by  forcing  the  ether- 
alcohol  solution  of  pyroxylin  through  glass  capillary  tubes  and  winding  them  on 


I?2  THE   TEXTILE  FIBRES. 

The  chief  drawback  to  the  rapid  progress  of  collodion  silk  is 
its  behavior  with  water.*  When  wetted  the  fibre  loses  its  orig- 
inal strength  to  such  a  degree  that  it  must  be  handled  with  great 
care.  Soap  solutions  and  free  dilute  acids  have  no  injurious 
effect,  but  free  alkalies  rapidly  disintegrate  the  fibre  and  finally 
dissolve  it  completely.  The  material  is  difficult  to  dye  on  account 
of  the  weakening  action  of  water,  and  the  operation  must  be 
carried  out  with  great  care.  The  dyeing  is  accomplished  with- 
out the  addition  of  either  soap  or  acid  to  the  bath.  The  basic 
coloring-matters  and  some  of  the  direct  cotton  colors  appear  to 
be  the  best  dyestuffs  to  employ. 

Besides  the  three  processes  already  given  of  obtaining  collo 
dion  silk,  there  are  other  methods  for  the  manufacture  of  this 
artificial  product.  Langhaus  employs  as  a  raw  material  a  prep- 
aration from  cellulose  and  sulphuric  acid.  Cadarat  uses  nitro- 
cellulose, dissolving  it  in  a  very  complex  mixture  of  glacial 
acetic  acid,  ether,  acetone,  alcohol,  toluol,  camphor,  and  castor-oil. 
This  forms  a  plastic  mass  which  is  treated  with  some  proteid 
substance,  such  as  gelatin  or  albumin  dissolved  in  glacial  acetic 
acid.  After  spinning,  the  fibres  are  treated  with  tannin  in  order 
to  render  them  elastic. 

Hoepfner  f  has  prepared  porous  acid-proof  fabrics  to  be 
employed  for  filtering  purposes  in  electrolytic  work  by  using  cot- 
ton yarn  which  has  been  nitrated.  The  latter  can  be  woven 
along  with  asbestos,  glass,  or  other  mineral  fibres  in  the  making 
of  the  fabric. 

frames.  As  the  solution  is  very  viscous,  it  requires  a  pressure  of  45  atmospheres 
to  discharge  it  through  the  capillary  openings.  It  was  formerly  the  custom  to 
furry  out  the  dyeing  of  pyroxylin  silk  in  the  pulp,  but  this  proved  to  be  imprac- 
tirabli-,  and  at  present  it  is  chiefly  dyed  in  the  form  of  yarn.  The  proportion 
between  the  price  of  natural  and  artificial  silk  is  approximately  as  follows:  Natu- 
ral silk,  Sio  per  kilo;  pyroxylin  silk,  $4.75  per  kilo;  gelatin  silk  (vanduara),  $2.40 
per  kilo. 

*  Artificial  silk  appears  incapable  of  withstanding  high  temperatures,  being 
rapidly  charred  and  destroyed  when  heated  to  150°  C.  A  method  for  the  analysis 
of  materials  containing  this  substance  has  been  proposed,  using  this  fact  as  a  basis. 
The  material  under  examination  is  heated  for  ten  minutes  at  200°  C.  Cotton, 
wool,  and  silk  are  not  materially  injured,  but  artificial  silk  is  completely  car  Urn 
i/rcl,  ;ind  on  rubbing  will  IK-  reduced  to  a  dust. 

t  Fdrber  Zeit.t  1897,  No.  5. 


ARTIFICIAL  SILKS;  LUSTRA-CELLULOSE.  173 

If  nitrated  cotton  be  examined  under  the  microscope,  a  con- 
siderable alteration  in  its  appearance  will  be  observed.  The 
fibres  are  much  thicker  in  the  wall,  and  are  consequently  stiff er 
than  those  of  ordinary  cotton.  The  lumen  has  either  vanished 
entirely  or  become  very  much  contracted,  and  this  appears  to  be 
due  to  the  swelling  of  the  cell-walls.  In  the  walls  of  the  fibre 
there  will  also  be  noticed  numerous  fractures  or  cracks  which  often 
assume  a  spiral  shape.  The  nitration  has  evidently  rendered  the 
fibre  much  more  brittle  and  has  decreased  its  elasticity. 

Solutions  of  nitrocellulose  have  been  employed  for  a  number  of 
purposes,  such  as  the  production  of  films  for  photographic  use, 
the  manufacture  of  lacquers,  etc.  The  author  has  also  success- 
fully utilized  sifth  a  preparation  for  the  waterproofing  of  paper 
and  other  materials.  It  also  forms  an  excellent  waterproof  sizing 
and  stiffening  agent  for  all  manner  of  textile  fabrics  and  hats. 

As  the  solutions  of  nitrocellulose  possess  great  viscosity,  it  is 
difficult  to  prepare  a  very  concentrated  solution.  The  addition  of 
formaldehyde  or  benzol,  however,  to  the  ordinary  solvents,  will 
increase  the  dissolving  capacity  considerably,  and  also  give  a 
more  mobile  solution.  Epichlor-  and  dichlorhydrms  also  act  as 
excellent  solvents  for  nitrocellulose,  being  capable  of  dissolving 
it  in  any  proportion. 

Vandnara  silk  *  is  a  thread  of  gelatin,  and  consequently  differs 
from  the  other  artificial  silks  in  that  it  consists  of  animal  tissue 
and  not  vegetable.  Due  to  this  circumstance  it  has  more  analogy 
chemically  to  true  silk  than  the  various  cellulose  silks.  The 
manufacture  of  vanduara  silk  is  conducted  by  pressing  an  aqueous 
solution  of  gelatin  through  a  fine  capillary  tube;  the  thread  so 
produced  is  carried  on  an  endless  band  through  a  drying-cham- 
ber. The  soft  gelatin  thread,  of  course,  flattens  out  considerably 
during  this  operation,  hence  the  silk  eventually  forms  a  flat,  rib- 
bon-like fibre.  After  drying  and  properly  reeling,  the  fibre  is 
treated  with  vapor  of  formaldehyde,  which  causes  the  gelatin  to 
become  insoluble  in  water.  By  varying  the  pressure  on  the 

*  Yanduara  silk  is  an  English  invention,  the  patentee  being  Adam  Millar. 
The  silk  has  never  appeared  on  the  market  as  a  commercial  commodity,  and 
the  process  does  not  seem  to  have  met  with  any  marked  degree  of  success. 


174  THE   TEXTILE  FIBRES. 

gelatin  solution,  whereby  it  is  forced  through  the  capillary  tube, 
the  thickness  of  the  fibre  may  be  increased  or  diminished.  The 
same  result  may  be  attained  by  varying  the  speed  of  the  endless 
band  which  carries  the  thread  after  coming  from  the  capillary 
tube.  The  silk  may  be  dyed  either  in  the  ordinary  way  in  skein 
form  after  reeling,  or  the  gelatin  solution  may  be  colored  before 
the  thread  is  drawn  out.  The  fibre  is  very  lustrous,  and  if  the 
filaments  are  drawn  fine  enough,  the  silk  is  soft  and  pliable. 

Hassac  *  gives  a  comparison  of  several  makes  of  artificial 
silk.  Chardonnet's  and  Lehner's  silks  are  very  similar  in  appear- 
ance; they  are  more  lustrous  than  real  silk,  but  are  stiffer,  and 
do  not  possess  the  characteristic  feel.  Cellulose  silk  made  by 
Pauly's  ammoniacal  copper  oxide  process  is  similar  to  the  former 
in  appearance,  but  its  lustre  is  even  better,  and  it  has  the  charac- 
teristic feel  of  true  silk.  Lehner's  silk  under  the  microscope  is 
characterized  by  deep  longitudinal  grooves  and  small  air-bubbles; 
its  cross-section  is  highly  irregular.  Pauly's  silk  shows  fine 
longitudinal  grooves,  and  minute  transverse  lines  in  the  centre 
of  the  fibres;  its  cross-section  is  regular,  approaching  a  circle  or 
ellipse.  Hammel's  gelatin  silk  is  almost  circular  in  outline, 
and  is  free  from  grooves  and  bubbles;  in  polarized  light  it  is 
singly  refracting,  while  the  others  are  doubly  so. 

As  the  collodion  silks  always  contain  some  nitro-compound, 
they  give  a  blue  color  with  diphenylamin  and  sulphuric  acid. 
Water  causes  all  the  artificial  silks  to  swell,  while  alcohol  or 
glycerin  contracts  them.  In  strong  sulphuric  acid  the  collodion 
silks  swell  rapidly  and  dissolve;  Pauly's  cellulose  silk  gradually 
becomes  thinner  and  dissolves;  gelatin  silk  only  dissolves  on 
strong  heating.  Chromic  acid  dissolves  all  artificial  silks  in  the 
cold;  real  silk  dissolves  but  slowly;  while  cotton  and  other  vege- 
table fibres  are  unaffected.  Caustic  potash  does  not  dissolve 
the  collodion  or  cellulose  silks,  but  both  the  gelatin  silk  and 
real  silk  are  soluble  on  boiling.  Schweitzer's  reagent  dissolves 
collodion  and  cellulose  silks;  whereas  gelatin  silk  is  insoluble,  but 
stains  the  liquid  a  bright  violet.  Alkaline  copper  glycerin  solu- 
tion at  80°  C.  dissolves  real  silk  immediately.  Tussah  and  gelatin 

*  Chem.  Zeil.,  190x3,  235,  267,  297. 


ARTIFICIAL  SILKS;   LUSTRA-CELLULOSE. 


silks  dissolve  when  boiled  for  one  minute ;  the  other  silks  are  not 
affected.  lodin  solution  colors  artificial  silks  an  intense  red, 
which  changes  to  a  transient  pale  blue  on  washing  with  water  in 
the  case  of  collodion  silks,  though  cellulose  silk  does  not  show 
this  blue.  lodin  and  sulphuric  acid  stain  true  silk  yellow, 
gelatin  silk  brown,  collodion  and  cellulose  silks  blue. 


Moisture. 

Fibres  to 
Sq.  Mm. 

Tens.  Strength, 
Kilo,  per 
Sq.  Mm. 

_ 

Exten- 

Silk. 

;bp.   lir. 

sion, 

Air- 

Satu- 

Per Ct. 

rated, 

Wet. 

Dry. 

Wet. 

Dry. 

Per  Ct. 

Per  Ct. 

Real  silk 

8   71 

20.  II 

16 

Q7IO 

Q7IO 

77    o 

•57    o 

21.6 

Chardonnet  

«j  .  1  1 
II  .  II 

27.46 

•  y 
•52 

V  /  iw 
640 

y  /  ivj 
H35 

J  1  •  v 
2.2 

o  1  •  u 
12.  O  ' 

'    8.0 

(Walston). 

11.32 

28.94 

•53 

683 

1620 

1.0 

22.3 

7-9 

Lehner  

10.45 

26.45!      -51 

413 

1180 

I»-5 

16.9 

7-5 

Paulv  

o.  20 

23.08 

-Q 

742 

I  ^^O 

3-  2 

IQ-'l 

12  .  s 

Oelatin 

V  •  *>\s 

13.98 

45  -56 

•37 

/  T"** 

265 

945 

0.0 

V 

6.6 

•*•  *"  •  j 

3-8 

Strehlenert  and  Westergren  give  the  following  figures  for  the 

tensile    strengths  of    various  natural  and   artificial  silks.     The 

figures  indicate  the  breaking   strains  in  kilograms  per  square 
millimeter  section: 

Natural  Silks. 

Dry.  Wet. 

Chinese  silk 53 . 2  46. 7 

French  raw  silk 50. 4  40. 9 

French  silk,  boiled-off 25 . 5  13-6 

"          "     dyed  red  and  weighted 20.0  15-6 

"         "     blue-black,  weighted  1 10% 12.1  8.0 

"         "     black,  weighted  140% 7.9  6.3 

"         "     black,  weighted  500% 2.2 

Artificial  Silks. 

Chardonnet's  collodion,  undyed 14. 7  1.7 

Lehner's  collodion,  undyed 17.1  4.3 

Strehlenert's  collodion,  undyed 15.9  3.6 

Pauly's  cuprammonium,  undyed 19.  i  3.2 

Viscose  silk,  early  samples 11.4  3.5 

"          "     latest  samples 21.5 

Cotton  yarn  (for  comparison) 1 1 . 5  18 . 6 

Cotton   may   be    ' '  animalized " — that   is,    given  the    dyeing 
properties   possessed  by   animal  fibres — in   a   variety  of   ways. 


1 76  THE    T^TILE  FIBRES. 

The  material  may  be  impregnated  with  albumin  and  afteflvards 
steamed;  this  method  is  employed  to  some  extent  in  printing, 
being  used  chiefly  in  connection  with  the  direct  cotton  colors,  to 
prevent  their  bleeding.  A  solution  of  casein  may  also  be  used 
instead  of  albumin,  with  similar  results.  The  same  property 
may  also  be  imparted  to  cotton  by  treatment  with  tannic  acid 
and  gelatin  or  lanuginic  acid,  but  with  doubtful  results;  though 
Knecht  describes  a  method  which  is  said  to  give  satisfaction,  the 
cotton  being  impregnated  with  a  solution  of  lanuginic  acid  and 
allowed  to  dry  in  the  presence  of  formaldehyde,  when  the  fibre 
becomes  coated  with  an  insoluble  film  possessing  a  remarkable 
affinity  for  the  substantive  dyes.  Vignon  claims  that  by  treating 
cotton  under  pressure  with  ammonia  in  presence  of  zinc  chloride 
or  calcium  chloride,  the  fibre  acquires  an  increased  affinity  for 
the  basic  and  acid  dyestuffs.  His  results,  however,  have  not 
been  confirmed. 

A  silk-like  appearance  may  also  be  given  to  vegetable  fibres 
by  treatment  with  a  solution  of  silk  (fibroin)  in  some  suitable 
solvent,  such  as  hydrochloric,  phosphoric,  sulphuric  acids,  or 
cuprammonium,  etc.  The  silk  employed  is  made  up  of  scraps 
and  waste  which  would  otherwise  be  useless.  Better  results  are 
obtained  if  the  cotton  material  be  treated  with  a  metallic  or  tannic 
acid  mordant  before  immersion  in  the  silk  solution,  and  should 
afterwards  be  calendered  and  polished  in  order  to  obtain  a  glossy 
appearance. 

Viscose  silk,  from  solutions  of  cellulose  thiocarbonate,  has 
been  made  with  some  degree  of  commercial  success  in  the 
United  States.  It  is  principally  made  in  coarse  numbers,  and  is 
used  as  an  artificial  horse-hair.  Finer  numbers  of  considerable 
softness  have  also  been  made,  for  use  in  braids,  passementerie, 
etc. 


CHAPTER  XIV. 

LINEN. 

I.  Preparation. — Linen  is  the  fibre  obtained  from  the  flax 
plant,  botanically  known  as  Linum  usitalissimum*  The  fibre  is 
prepared  from  the  bast  of  the  plant  by  a  process  called  retting, 
which  has  for  its  purpose  the  separation  of  the  fibrous  cellulose 
from  the  woody  tissue  and  other  plant  membranes.  Historically, 
linen  appears  to  have  been  the  earliest  vegetable  fibre  employed  in- 
dustrially, having  been  used  at  a  much  earlier  date  than  cotton. 
Though  grown  more  or  less  in  every  country,  at  present  the 
cultivation  of  flax  is  principally  carried  on  in  France,  Ireland, 
Belgium,  Holland,  Russia,  America,  and  Canada.  The  bast 
tissue,  which  is  used  for  the  fibre,  is  situated  between  the  bark 
and  the  underlying  woody  tissue. 

The  flax  plant,  after  attaining  its  proper  growth,  is  either  cut 
down  or  pulled  up  by  its  roots,  and  subjected  to  a  process  tech- 
nically known  as  rippling,  the  plants  being  drawn  through  a 
machine  which  removes  the  seeds  and  leaves,  f  •  The  remaining 

*  Botanists  recognize  upwards  of  one  hundred  species  of  the  flax  plant,  but, 
of  all  these,  the  only  one  possessing  industrial  importance  and  the  only  one 
readily  cultivated  is  the  Linum  usitatissimum  (or  L.  commun),  which  has  a  blue 
flower.  The  North  American  Indians  have  long  used  the  fibre  of  L.  luvisii, 
which  differs  from  the  ordinary  cultivated  flax  in  having  three  stems  growing 
from  a  perennial  root.  The  most  ancient  species  of  flax  brought  under  cultiva- 
tion is  thought  to  be  L.  angustijolium;  the  Swiss  lake-dwellers  are  said  to  have 
grown  it,  as  also  the  ancient  inhabitants  of  northern  Italy.  The  flax  culti- 
vated in  the  eastern  countries,  in  Assyria,  and  EgypUappears  to  have  been  the 
common  variety  L.  usitatissimum. 

f  Besides  being  cultivated  for  its  fibre,  the  flax  plant  is  also  grown  for  its  seed, 
which  yields  the  valuable  oil  known  as  linseed.  It  possesses  good  drying  qualities, 

177 


173  THE   TEXTILE  FIBRES. 

stalks  are  then  tied  in  bundles  and  placed  in  stagnant  water, 
where  they  are  allowed  to  remain  for  a  number  of  days.  Active 
fermentation  soon  starts,  resulting  in  the  decomposition  of  the 
woody  tissues  enclosing  the  cellulose  fibres.  When  the  process 
has  gone  sufficiently  far,  the  bundles  of  fermented  stalks  are 
removed  and  passed  through  a  number  of  mechanical  operations, 
whereby  the  decomposed  tissues  are  removed  and  the  linen  fibres 
are  isolated  in  a  purified  condition.  This  method  of  retting 
with  stagnant  water  is  known  as  " pool- retting."  As  the  fer- 
mentation causes  the  evolution  of  considerable  gas,  in  order  to 
keep  the  bundles  of  stalks  submerged  they  are  loaded  with  stones 
or  boards.  The  time  of  steeping  in  the  water  varies  with  cir- 
cumstances from  five  to  ten  days.  Another  method  of  retting 
is  to  steep  in  running  water.  The  famous  Courtrai  flax  of  Bel- 
gium is  retted  in  this  manner  in  the  river  Lys.  The  flax- straw, 
after  pulling,  is  placed  in  crates  and  submerged  in  the  water  of 
this  stream  for  a  period  of  four  to  fifteen  days,  depending  on  the 
temperature  and  other  influences.  Courtrai  flax  is  of  a  creamy 
color,  whereas  pool-retted  flax  is  a  rather  dark  bluish  brown 
color.  The  excellent  qualities  of  the  Courtrai  flax  are  said  to  be 
due  to  the  action  of  the  soft,  slowly  running,  almost  sluggish 
waters  of  the  river  Lys,  and  to  the  peculiar  ferment  existing 
therein.  Another  method  employed  for  obtaining  the  fibre  from 
flax  is  known  as  dew-retting,  as  the  flax-straw  is  spread  out  in  a 
field  and  exposed  for  a  couple  of  weeks  to  the  action  of  the  dew 
and  the  sun.  Dew-retting,  however,  gives^the  most  uneven  and 
least  valuable  product  of  the  three  methods  employed,  and  the 
fibre  is  rather  dark  in  color.  There  have  also  been  several  chemi- 
cal methods  proposed  for  retting  flax,  such  as  heating  with  water 
under  pressure,  boiling  with  solutions  of  oxalic  acid,  soda-ash, 
caustic  soda,  etc.  None  of  these,  however,  have  proved  of  any 
industrial  value,  and  the  old  natural  methods  are  still  adhered 

and  hence  is  extensively  lised  for  the  preparation  of  paints  and  varnishes.  The 
best  seed-flax  is  grown  in  tropical  and  subtropical  countries,  whereas  the  best 
fibn-llax  is  grown  in  more  northern  climates.  The  seed  obtained  from  the  latter 
variety,  though  utilized  as  a  by-product,  produces  only  an  inferior  grade  of  oil. 
The  oil-cake  left  after  expressing  the  oil  from  the  seed  is  an  excellent  cattle-food 
and  is  largely  used  for  this  purpose. 


LINEN.  179 

to.  Additions  of  various  chemicals  to  the  retting  waters  have  at 
times  proved  of  value,  hydrochloric  or  sulphuric  acid  sometimes 
being  used  to  advantage.* 

Th'e  intercellular  substance  holding  the  flax  fibres  together 
consists  mostly  of  calcium  pectate,  and  the  real  object  of  retting 
is  to  render  this  substance  soluble  so  that  it  may  be  removed  by 
the  after- processes  of  treatment.  Winogradsky  has  succeeded  in 
isolating  the  particular  organism  that  is  the  active  agent  in  the 
pectin  fermentation.  It  is  an  anaerobic  bacillus  which  readily 
ferments  pectin  matters,  but  has  no  action  on  cellulose.  By 
adding  salts  promoting  the  growth  of  the  bacillus  to  the  water 
employed  in  retting,  it  has  been  found  possible  to  reduce  the 
time  of  retting  very  considerably.  It  has  been  claimed  that 
fatty  acids  exert  a  solvent  action  on  the  resinous  and  pectin  mat- 
ters present  in  vegetable  fibres,  and  a  method  for  the  decortication 
of  flax  and  other  bast  fibres  has  been  devised  as  follows:  The 
raw  fibres  are  impregnated  with  boiling  soap  solutions,  after 
which  ammonium  chloride  is  added,  which  liberates  the  fatty 
acids.  After  several  hours'  treatment  these  dissolve  all  gummy 
and  resinous  matters;  the  fibres  are  then  treated  with  weak 
caustic  alkali,  after  which  they  are  washed  and  dried,  when  they 
should  be  thoroughly  disintegrated.  Ramie  may  be  treated  with 
borated  water.  Good  results  are  said  to  be  obtained  by  this 
method. 

The  flax  stalks,  after  rippling  and  being  deprived  of  their 
leaves  and  seeds,  are  known  as  flax-straw.  The  latter  in  the  air- 
dry  condition  contains  from  73  to  80  per  cent,  of  wood,  marrow,  and 
bark,  and  20  to  27  per  cent,  of  bast.  The  general  structure  of  flax- 
straw,  and  of  bast  stalks  in  general,  is  shown  in  the  schematic 
drawing  (Fig.  38). 

The  linen  fibre  as  it  is  obtained  from  the  plant  and  as  it  appears 
in  trade  is  in  the  form  of  filaments  the  length  of  which  varies 

*  Schenk's  method  of  retting  is  to  steep  in  warm  water,  a  constant  temperature 
of  35°  C.  being  maintained.  It  is  said  that  the  fermentation  may  be  completed 
by  this  method  in  fifty  to  sixty  hours,  and  gives  a  larger  yield  and  a  better  product 
than  the  natural  processes  of  retting.  In  steam-retting,  the  bundles  of  flax-straw 
are  placed  in  iron  cylinders  and  heated  with  live  steam  or  hot  water  under  pressure; 
but  the  process  does  not  appear  to  be  successful. 


i8o 


THE    TEXTILE  FIBRES. 


considerably  with  the  manner  and  care  employed  in  decorticating, 
and  may  be  from  a  few  inches  to  several  feet.  These  filaments 
are  composed  structurally  of  small  elements  or  cells.  Wiesner 
gives  the  following  dimensions  of  several  varieties  of  flax  fila- 
ments : 


Kind  of  Flax. 

Mean  Length 
of  the  Purified 
Flax  Fibre, 
mm. 

Mean  Breadth, 
mm. 

EtrvDtian 

q6o 

o.  2?"; 

Westphalian          

7^0 

O.  114 

Belgian  Courtrai  

37O 

O.  l<X 

Austrian  

410 

o.  202 

Prussian  

280 

o.  no 

2.  Chemical  and  Physical  Properties. — The  flax  fibre  appears 
to  consist  of  pure  cellulose  *  and  shows  no  signs  at  all  of  being 
lignified.  It  is  strongly  swollen  by  treatment  with  Schweitzer's 
reagent,  but,  unlike  cotton,  it  does  not  completely  dissolve  therein. f 

The  color  of  the  best  varieties  of  flax  is  a  pale  yellowish  white. 
Flax  retted  by  means  of  stagnant  water,  or  by  dew,  is  a  steel-gray; 
and  Egyptian  flax  is  a  pearl-gray.  The  pale-yellow  color  of  flax 
is  due  to  natural  pigment,  but  the  other  color  arises  from  the 
decomposition  of  the  intercellular  matter,  which  is  left  as  a  stain 
on  the  fibre.  Flax  that  has  been  imperfectly  retted  shows  a 

*  In  order  to  isolate  pure  flax  cellulose,  Cross  and  Bevan  have  recommended 
the  following  procedure:  The  non-cellulosic  constituents  of  flax  are  pectic  com- 
pounds which  are  soluble  in  boiling  alkaline  solutions.  The  proportion  of  such 
constituents  varies  from  14  to  33  per  cent,  in  different  varieties  of  flax.  They  may 
be  completely  extracted  by  first  boiling  the  fibre  in  a  dilute  solution  of  caustic 
soda  (i  to  2  per  cent.) ;  the  residue  will  consist  of  flax  cellulose,  with  email  remnants 
of  woody  and  cuticular  tissue,  together  with  some  of  the  oils  and  waxes  associated 
with  the  latter.  By  treatment  with  a  weak  solution  of  chloride  of  lime,  the  woody 
tissue  is  decomposed,  and  is  then  removed  by  again  boiling  in  dilute  alkali.  The 
remaining  cellulose  is  then  further  purified  from  residual  fatty  and  waxy  matters 
by  boiling  with  alcohol  and  finally  with  ether-alcohol  mixture.  Flax  cellulose 
prepared  in  this  manner  appears  to  be  chemically  indistinguishable  from  cotton 
cellulose. 

f  In  swelling,  the  fibre  blisters  considerably,  but  not  in  as  regular  a  manner  as 
cotton.  The  inner  layers  of  the  cell  withstand  the  action  of  the  reagent  the  longest 
and  remain  floating  in  the  liquid,  like  the  cuticle  of  cotton.  Parenchym  and 
intercellular  matter  adhering  to  the  fibre  also  remain  undissolved  in  the  reagent. 


LINEN. 


181 


greenish  color.  The  natural  color  of  linen  is  readily  bleached 
by  solutions  of  chloride  of  lime  in  a  manner  similar  to  the  bleach- 
ing of  cotton.  But  the  linen  fibre  suffers  considerable  deteriora- 
tion thereby.  There  are  four  grades  of  linen-bleaching — quar- 
ter, half,  three-quarters,  and  full  bleach.  The  whiter  the  fibre 
is  bleached,  the  weaker  it  becomes.  The  lustre  of  linen  is  quite 
pronounced  and  almost  silky  in  appearance;  flax  that  is  over- 
retted  is  dull  in  appearance.  Egyptian  flax  is  also  dull,  due  to- 
the  cells  being  coated  with  residual  intercellular  matter. 

The  flax  fibre  is  much  stronger  than  that  of  cotton,  though 
overretted  flax  is  brittle  and  weak. 

The  bast-cells  of  the  flax  fibre  may  be  isolated  by  treatment 
with  a  dilute  chromic  acid  solution.  They  are  cylindrical  in 


A  B 

FIG.  3;a. — Micrograph  of  Flax  Fibre. 

A,  longitudinal  view,  showing  jointed  structure  and  tracing  of  lumen;  B,  cross- 
sections. 

form  and  taper  to  a  point  at  each  end.  At  the  middle  they 
measure  12  to  26  //,  with  an  average  of  about  15  //.*  The 
length  varies  from  4  to  66  mm.,  with  an  average  of  about 
25  mm.  The  ratio  of  the  length  of  the  fibre  'to  its  breadth  is 
about  1200.  Under  the  microscope  the  surface  of  the  fibre  ^ 
appears  smooth  or  marked  longitudinally,  with  frequent  trans- 

-\—i — 

*  According  to  Vetillard,  15-37  fi   with  an  average  of  22  ft. 


i82  THE    TEXTILE  FIBRES. 

verse  fissure  lines  and  jointed  structures.  On  treatment  with 
chloriodide  of  zinc  the  latter  are  colored. much  darker  than  the 
rest  of  the  fibre  and  are  thus  rendered  more  apparent.  The 
lumen  appears  in  the  centre  of  the  fibre  as  a  narrow  yellow  line, 
and  it  is  usually  completely  filled  with  protoplasm.  In  cross- 
section  the  fibres  of  flax  are  polygonal,  with  rounded  edges,  show 
a  large  lumen,  and  a  relatively  thin  cell-wall.  In  these  respects 
they  are  very  similar  to  hemp,  but  may  be  distinguished  from  the 
latter,  however,  in  that  they  do  not  aggregate  in  thick  bundles, 
but  are  more  or  less  isolated  from  each  other,  so  that  the  cross- 
section  frequently  shows  but  one  fibre,  and  seldom  more  than 
three  or  four*  (see  Fig.  370). 

The  following  analyses  show  the  composition  of  twp  typical 
specimens  of  flax  (H.  Mtiller) : 

i.  ii. 

Per  Cent.  Per  Cent. 

Water  (hygroscopic) 8. 65  10.  70 

Aqueous  extract 3-65  6.02 

Fat  and  wax 2 . 39  2 . 37 

Cellulose 82.57  7l-5Q 

Ash  (mineral  matter) 0.70  1.32 

Intercellular  matter 2 . 74  9 . 41 

Highly  purified  flax  appears  to  approximate  very  closely  to 
the  composition  of  cotton.  The  ordinary  flax  fibre  of  trade  may 
be  said  to  contain  about  5  per  cent,  less  of  cellulose  than  cotton, 
there  being  about  that  much  more  impurity  present  in  the  form 
of  intercellular  matter  and  pectin  bodies. f  The  hygroscopic 

*  Other  differences  from  hemp  exhibi^d  by  the  linen  fibre  are:  (a)  the  cross- 
section  does  not  show  an  external  yellow  layer  of  lignin  when  treated  with  iodin 
and  sulphuric  acid;  (6)  it  gives  reactions  for  pure  cellulose  only,  ihat  is,  iodin  and 
sulphuric  acid  color  the  fibre  a  pure  blue,  and  anilin  sulphate  gives  no  color, 
though  at  times  there  are  shreds  of  parenchym  tissue  present  which  are  colored 
yellow  by  this  latter  reagent  and  appear  to  be  lignified;  (c)  the  lumen  of  the  hemp 
fibre  is  seldom  filled  with  yellowish  protoplasm  like  that  of  the  linen  fibre;  (d)  the 
linen  fibres  end  in  sharp  points,  whereas  those  of  hemp  do  not. 

t  The  flax  fibre  contains  a  certain  wax-like  substance,  varying  in  amount 
from  0.5  to  2  per  cent.  It  may  be  extracted  from  the  fibre  by  means  of  benzene 
or  ether.  The  color  of  the  wax  obtained  varies  with  that  of  the  flax  from  which 
it  is  obtained.  It  has  a  rather  unpleasant  odor,  resembling  flax  itself.  Its  melting- 
point  is  61.5°  C.,  and  its  specific  gravity  ;it  60°  F.  is  0.9083.  According  to  Hof- 
meister  this  wax  consists  of  81.32  per  cent,  of  unsaponifiablc  waxy  matter  and 


LINEN.  183 

moisture  in  linen  is  about  the  same  as  in  cotton;  in  fact,  all  vege- 
table fibres  appear  to  contayi  approximately  the  same  amount 
(from  8  to  10  per  cent.). 

Due  to  differences  in  structure,  linen  is  more  easily  disinte-1^ 
grated  than  cotton,   and  consequently  does  not  withstand  the 
action  of  boiling  alkaline  solutions,  solutions  of  bleaching  pow- 
der or  other  oxidizing  agents,  etc.,  as  well  as  cotton. 

Towards  mordants  and  dyestuffs,  etc.,  linen  does  not  react  as   ( 
readily  as  cotton,  hence  its  manipulation  in  dyeing  is  more  diffi- 
cult.    In  general,  however,  it  may  be  said  that  the  dyeing  and 
treatment  of  linen  are  practically  the  same  as  with  cotton. 

The  oil-wax  group  of  constituents  in  the  flax  fibre  plays  an 
important  part  in  the  spinning  of  this  fibre,  and  the  failure  of 
many  of  the  artificial  processes  of  retting  flax  may  be  attributed 
to  the  fact  that  the  fibre  is  left  with  a  deficiency  of  these  constitu- 
ents. In  the  breaking  down  of  the  cuticular  celluloses,  whether 
in  the  retting  or  in  the  bleaching  processes,  these  waxes  and  oils 
are  separated.  Their  complete  elimination  from  the  cloth  neces- 
sitates a  very  elaborate  treatment,  such  as  is  represented  by  the 
"Belfast  Linen  Bleach." 

18.68  per  cent,  of  saponifiable  oil.  Of  the  latter,  54.49  per  cent,  is  free  fatty 
acid.  The  waxy  matter  has  a  melting-point  of  68°  C.,  and  apparently  is  a  mixture 
of  several  bodies.  The  principal  one  resembles  ceresin,  and  there  is  also  present 
ceryl  alcohol  and  phylosterin.  The  saponifiable  matter  appears  to  contain  small 
quantities  of  soluble  fatty  acids,  like  caproic,  stearic,  palmitic,  oleic,  linolic,  linolenic, 
and  isolinolenic. 


CHAPTER  XV. 

JUTE,    RAMIE,   HEMP,   AND   MINOR   VEGETABLE    FIBRES. 

i.  Jute  is  a  fibre  obtained  from  the  bast  of  various  species  of 
Corchorus,  growing  principally  in  India  and  the  East  Indian 
Islands.  The  most  important  variety  is  Corchorus  capsularis, 
which  is  grown  throughout  tropical  Asia  not  only  as  a  fibre-plant, 
but  also  as  a  vegetable.  Other  varieties  are  C.  olitorius,  C.  juscus, 
and  C.  decemangulatus;  the  latter  two,  however,  yield  but  a  small 
proportion  of  the  jute  fibre  to  be  found  in  trade.*  The  jute 
plant  grows  to  a  height  of  10  to  12  ft.  and  its  fibrous  layer  is  very 
thick,  so  that  it  yields  from  two  to  five  times  as  much  fibre  as  flax. 

The  preparation  of  the  fibre  from  the  jute  plant  is  a  rather 
simple  operation.  The  stalks  are  freed  from  leaves,  seed- cap- 
sules, etc.,  and  retted  by  steeping  in  a  sluggish  stream  of  water. 
After  a  few  days  the  bast  becomes  disintegrated,  and  the  retted 
stalks  are  pressed  and  scutched.  The  fibre  so  obtained  is  re- 
markably pure  and  free  from  adhering  woody  fibre  and  other 
tissue.  The  prepared  fibre  usually  has  a  length  of  from  4  to  7  ft., 
possesses  a  pale  yellowish  brown  color,  and  exhibits  considerable 
lustre  and  tensile  strength.  The  ends  of  the  plant,  together  with 
the  various  short  waste  fibres,  appear  in  trade  under  the  name  of 
"jute  butts"  or  " jute  cuttings,"  and  are  employed  as  a  raw  ma- 
terial for  paper-manufacturing. 

*  The  commercial  fibre  known  as  Chinese  jute  is  not  a  variety  of  jute  at  all, 
but  is  derived  from  Abutilon  avicenna  or  Indian  mallow.  The  latter  grows 
extensively  as  a  weed  in  America.  The  bast  fibre  is  white  and  glossy,  and  has 
considerable  tensile  strength.  It  is  also  vised  for  the  making  of  paper  stock. 
Chemically  it  appears  to  consist  of  bastose,  and  hence  resembles  jute  in  its  behavior 
towards  dyestuffs.  The  plant  produces  about  20  per  cent,  of  fibre,  but  is  of  doubt- 
ful economic  value. 

184 


JUTE,   RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.       185 


531 


According  to  Hohnel  the  bast-cells  of  the  jute  fibre  are  1.5  to 
5  mm.  in  length,  and  from  20  to  25  /*  in  thickness,  the  mean 
ratio  of  the  length  to  the  breadth  being 
about  90;  consequently  the  elements  of  the 
jute  fibre  are  relatively  short.  In  cross- 
section  the  jute  fibre  shows  a  bundle  of 
several  elements  bound  together;  these  are 
more  or  less  polygonal  in  outline,  with 
sharply  defined  angles.  Between  the  sepa- 
rate elements  is  a  narrow  median  layer 
(see  Figs.  40  and  41),  which,  however,  does 
not  give  a  much  darker  color  with  iodin  and 
sulphuric  acid  than  the  cell-wall  itself. 
The  lumen  is  about  as  wide,  or  at  times 
even  wider,  than  the  cell-wall,  and  in  cross- 
section  is  round  or  oval.  Longitudinally, 
the  lumen  shows  remarkable  constrictions 
(see  Fig.  39),  though  towards  the  end  of 
the  fibre  the  lumen  broadens  out  consider- 
ably, causing  the  cell- wall  to  become  very  JFic.  38.— Diagram  of 

.  .          _          '  .        -,          .  jX  Flax-straw.     (Witt.) 

thin.     Externally  the  fibre  is   smooth  and/  ^  marrow.    2>    woody 
lustrous,  and    has    no    jointed    ridges    or       fibre;     3,    cambium 

.  .  ,  ...  layer;  4,  bast  fibre;  5, 

transverse  markings  such  as  seen  in  linen  or     *  rind  or  bark, 
most  other  bast  fibres. 

In  its  chemical  composition  jute  is  apparently  quite  different  \x^ 
from  linen  and  cotton,  being  composed  of  a  modified  form  of 
cellulose  known  as  lignocellulose  or  bastose.  Bastose,  properly 
speaking,  is  a  compound  of  cellulose  with  lignin.*  It  behaves 
quite  differently  from  celullose  towards  various  reagents,  its  chief 
distinction  being  that  it  is  colored  yellow  by  iodin  and  sulphuric 
acid,  whereas  pure  cellulose  is  colored  blue.  The  following  table 
gives  the  principal  reactions  used  to  distinguish  cellulose  from 
bastose : 


*  Miiller  gives  the  following  method  for  the  isolation  of  pure  cellulose  from 
jute:  Two  grams  of  the  material  are  dried  at  no0  to  115°  C.  In  order  to  remove 
wax,  etc.,  it  is  next  treated  with  a  mixture  of  alcohol  and  benzol,  and  is  subse- 
quently boiled  with  very  dilute  ammonia  water.  The  softened  mass  is  then 


i86 


THE   TEXTILE  FIBRES. 


Reagent. 

Cellulose. 

Bastose. 

lodin  and  sulphuric  acid  . 
Anilin  sulphate  and  sul- 
phuric acid 

Blue  color 
No  change 

Yellow  to  brown  color 
Deep-yellow  color 

Basic  dyestuffs 

No  change 

Becomes  colored 

Weak  oxidizing  agents  .  .  . 
Schweitzer's  reagent.  .  .  . 

No  change 
Quickly  dissolves 

Quickly  decomposes 
Swells,  becomes  blue,  and  slowly 

dissolves 

Analysis  of  the  jute  fibre  shows  it  to  consist  of  the  following: 


Constituents. 

Nearly  Color- 
less Specimen. 

Fawn  -colored 
Fibre. 

Brown 
Cuttings. 

Ash 

0  68 

\\ater  (hygroscopic).  .  .         

O.Q-J 

0   64 

12   q8 

Aqueous  extract  

I  .03 

1.6? 

7  .04 

Fat  and  wax  

O.  3Q 

O.  T.2 

0.4=; 

Cellulose 

64    24. 

63    OS 

6l    74 

Incrusting  and  pectin  matters 

24.    4.1 

2s     ^6 

2  1    2Q 

The  ash  of  jute  consists  principally  of  silica,  lime,  and  phos- 
phoric acid;  manganese  is  nearly  always  present  in  small 
amount.* 

Bastose  is  dissolved  by  the  usual  cellulose  solvents,  such  as 
zinc  chloride  and  Schweitzer's  reagent;  and  from  these  solutions 
the  lignocellulose  may  be  precipitated  by  dilution  or  acidifying, 
respectively,  though  the  precipitation  is  never  complete,  there 
remaining  in  solution  about  15  to  25  per  cent,  of  the  original 
substance. 


pulverized  in  a  mortar,  and  placed  in  a  large,  glass-stoppered  flask  with  100  c.c. 
of  water.  From  5  to  10  c.c.  of  a  solution  of  2  c.c.  of  bromin  in  500  c.c.  of  water 
are  added,  until  a  permanent  yellow  color  is  obtained  after  standing  twelve  to  twenty- 
four  hours.  The  substance  is  then  filtered,  washed  with  water,  and  heated  to 
boiling  with  water  containing  a  little  ammonia.  After  this  it  is  filtered,  washed,  and 
again  treated  with  the  bromin  solution,  as  above  indicated,  until  a  permanent 
yellow  color  is  obtained.  The  fibre  is  then  boiled  with  dilute  ammonia,  and  on 
filtering  and  washing  leaves  a  residue  of  purr  white  cellulose. 

*  According  to  Cross  and  Bevan  the  jute  fibre  may  be  regarded  as  an  anhydro- 
aggregate  of  three  separate  compounds:  (a)  A  dextrocellulose  allied  to  cotton; 
(b)  a  pentacellulose  yielding  furfural  and  acetic  acid  on  hydrolysis;  (c)  lignone, 
a  quinone  which  is  converted  by  chlorination  and  reduction  into  derivatives  of 
the  trihydric  phenols. 


JUTE,   RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.       187 

The  chief  chemical  difference  between  jute  and  the  pure  ceP"" 
lulose  fibres  is  in  the  ability  of  the  former  to  combine  directly 
with  basic  dyestuffs.     In  fact,  it  acts  in  this  respect  similar  to 


FIG.  39. — Cross-section  of  Flax-straw.     (Cross  &  Bevan.) 

A,  layer  of  cuticular  cells;  B,  intermediate  layer  of  cortical  parenchyma;  C,  bast 
fibres  in  groups,  being  the  flax  fibres  proper;  note  secondary  thickening  of 
cell-walls;  D,  cambium  layer;  E,  woody  tissue. 

u 

cotton  which  has  been  mordanted  with  tannic  acid.     Jute  is  also 

more  sensitive  to  the  action  of  chemicals  in  general  than  cotton  or 
linen.  On  this  account  it  cannot  be  bleached  with  much  success, 
as  treatment  with  alkalies  and  bleaching  powder  weakens  and 
disintegrates  the  fibre  to  a  considerable  extent. 


1 88  THE   TEXTILE  FIBRES. 

The  jute  fibre  is  relatively  weak  when  compared  with  other 

*t    bast  fibres,  and  the  chief  reasons  for  its  prominence  among  the 

textile  fibres  are  its  fineness,  silk-like  lustre,  and  adaptability  for 

spinning.     The  plant  is  also  easy  to  cultivate,  and  returns  a  large 

*j  yield  of  fibre.     The  chief  defect  of  jute  is  its  lack  of  durability; 

^/when  exposed  to  dampness  it  rapidly  deteriorates;  and  even  under 

ordinary  conditions  of  wear,  the  fibre  gradually  becomes  brittle 

and  loses  much  of  its  strength.     The  bleached  fibre  is  especially 

liable  to  such  deterioration;    it  gradually  loses  its  whiteness,  and, 

evidently  due  to  oxidation,  becomes  dingy  and  yellowish  brown 

in  color. 

Jute  is  principally  used  for  the  making  of  coarse  woven  fabrics, 
such  as  gunny  sacks  and  bagging,  where  cheapness  is  of  more 
consequence  than  durability.  It  also  finds  considerable  use  in 
the  tapestry  trade,  being  used  as  a  binding-thread  in  the  weaving 
of  carpets  and  rugs.  On  account  of  its  high  lustre  and  fineness, 
it  is  also  adapted  for  the  preparation  of  cheap  pile  fabrics  for  use 
in  upholstery.  Of  late  years  a  variety  of  novelty  fabrics  for  dress- 
goods  have  also  been  made  from  jute,  used  in  conjunction  with 
woolen  yarns.  Jute  has  also  been  used  extensively  as  a  substitute 
for  hemp,  for  which  purpose  the  former  is  rendered  very  soft  and 
pliable  by  treatment  with  water  and  oil.  A  mixture  of  20  parts 
of  water  with  2.5  parts  of  oil  is  sprinkled  over  100  parts  of  jute 
fibre.  It  is  left  for  one  to  two  days,  then  squeezed  and  heckled, 
whereby  the  fibres  become  very  soft  and  isolated.  Jute  is  also 
largely  used  in  the  manufacture  of  twine  and  smaller  sizes  of 
rope.  Owing  to  its  cheapness  it  is  used  to  adulterate  other  more 
valuable  fibres,  but  due  to  its  tendency  to  rapid  deterioration,  its 
use  in  this  connection  should  not  be  encouraged.  The  "jute 
butts"  and  miscellaneous  waste  are  extensively  employed  as  a 
raw  material  in  the  manufacture  of  paper. 

2.  Ramie,  or  China  Grass,  is  a  fibre  obtained  from  the  bast  of 
the  stingless  nettle,  or  Bcehmeria.  Although  frequently  con- 
founded in  trade,  ramie  and  China  grass  are  in  reality  two  dis- 
tinct fibres.  The  former  (also  known  as  rhea)  is  obtained  from 
the  Bcehmeria  tenacissima,  which  grows  best  in  tropical  and  sub- 
tropical countries.  The  latter  is  obtained  from  Bcehmeria  nivea, 
which  grows  principally  in  the  more  temperate  climes.  TJ^e 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.       i89 


two  species,  however,  are  so  similar  in  nature,  and  the  fibres  are 
so  universally  confounded  with  one  another,  that  it  is  only  possi- 
ble to  consider  them  as  a  single  substance,  which  will  be  done 
under  the  name  of  ramie.  The  plant  is  a  shrub,  reaching  4  to 
6  ft.  in  height,  and  is  very  hardy.  It  is  cultivated  largely 
in  China  and  India,  and  has  also  been  grown  successfully  in 
America. 

The  fibre  of  ramie  is  very  strong  and  durable,  probably  rank- 
ing first  of  all  vegetable  fibres  in  this  respect.  It  is  also  the  least 
affected  by  moisture.  It  has. three  times  the  strength  of  hemp, 
and  the  fibres  can  be  separated  to  almost  the  fineness  of  silk. 
The  fibre  is  exceptionably  white  in  color,  being  almost  compa- 
rable to  bleached  cotton  in  this  respect,  and  does  not  appear  to 
have  any  natural  coloring-matter  at  all.  It  also  has  a  high  lustre, 
excelling  linen  in  this  respect. 

The  following  table  gives  the  chief  physical  factors  of  the  ramie 
fibre  in  comparison  with  the  other  principal  fibres: 


Ramie. 

Hemp. 

Flax. 

Silk. 

Cotton. 

Tension                          ......... 

IOO 

^6 

2s 

1  2 

Elasticity                        

IOO 

75 

66 

*o 

4.OO 

Torsion            

IOO 

QC 

80 

6co 

Having  such  excellent  qualities  as  a  fibre,  it  would  be  natural 
that  ramie  should  have  had  considerable  attention  bestowed  upon 
it.  The  chief  difficulty  in  the  way  of  its  universal  and  wide-spread 
adoption  has  been  the  lack  of  an  efficient  process  for  properly 
decorticating  the  fibre  from  the  rest  of  the  plant.  In  China  and 
India,  where  this  fibre  has  long  been  employed  for  the  weaving  of 
the  finest  and  most  beautiful  fabrics,  the  decortication  of  the 
fibre  is  carried  out  by  hand.  This,  of  course,  would  be  imprac- 
ticable in  western  countries. 

On  French  authority  it  is  stated  that  the  yield  of  decorticated 
fibre  from  the  green,  unstripped  stalks  amounts  to  about  2  per 
cent.,  and  of  degummed  fibre  about  i  per  cent.  Based  on  the 
weight  of  dry,  stripped  stalks,  the  yield  of  the  degummed  fibre 
would  be  about  10  per  cent. 


190 


THE   TEXTILE  FIBRES. 


The  bast  of  the  ramie  cannot  be  removed  from  the  woody 
tissue  in  which  it  is  imbedded  by  a  simple  retting,  as  in  the  case  of 
flax  and  other  bast  fibres.  It  must  undergo  a  severe  mechanical 
treatment,  whereby  the  outer  bark  is  removed.  The  long,  fibrous 
tissue  so  obtained  consists  of  the  ramie  filaments  held  together  in 
the  form  of  a  ribbon  by  a  large  quantity  of  gum,  and  before  the 
fibres  can  be  combed  out  this  gum  must  be  removed  by  chemical 
treatment.  The  gummy  matters  seem  to  consist  esssentially  of 
pectose,  cutose,  and  vasculose.  In  the  degumming,  the  object  is 
to  remove  these  substances  without  affecting  the  cellulose  of  the 
fibre  proper.  The  vasculose  and  cutose  may  be  dissolved  by 
treatment  with  alkaline  oleates  or  caustic  alkalies  employed 
under  pressure.  The  adhering  pectose  can  then  be  detached 
mechanically  by  washing. 

Though  ramie  has  many  excellent  qualities  to  recommend  it 
as  a  textile  fibre  for  definite  uses,  nevertheless  it  lacks  the  elas- 


FIG.  40.— Jute  Fibre. 

A,  middle  portion;  B,  end  of  fibres;  /,  lumen;    k,  knot-like  joints;     C,  cross- 
sections;  m,  median  layers  between  fibres.  ' 

v  ticity  of  wool  and  silk  and  the  flexibility  of  cotton.     As  a  result 

'  it  yields  a  harsher  fabric,  which  has  not  the  softness  of  cotton. 

Owing  to  its  smooth  and  regular  surface  it  also  becomes  difficult 

to  spin  into  fine  counts,  as  the  fibres  lack  cohesion  and  will  not 

adhere  to  each  other. 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.      191 


Microscopically,  the  ramie  fibre  is  remarkable  for  the  large 
size  of  its  bast-cells.  These  are  from  60  to  250  mm.  in  length  and 
up  to  80  fi  in  width.  The  ratio  of  the  length  to  the  breadth  is 
about  2400.  The  fibre  consists  of  pure  cellulose  with  no  indica- 
tion of  the  presence  of  any  lignin.  Along  the  fibre,  joints  and 
transverse  fissures  are  of  frequent  occurrence  (see  Fig.  42).  The 
lumen  is  especially  broad  and  easily  noticeable.  The  ends  of  the 
fibre  elements  have  a  thick- walled,  rounded  point,  and  the  lumen 
is  reduced  to  a  line.  The  cross-section  of  the  fibre  (see  Fig.  43) 
shows  usually  only  a  single  element  or  a  group  of  but  a  few  mem- 
bers. The  cross-section  is  also  quite  large,  and  is  elliptical  in 
shape;  the  lumen  appears  open,  and  frequently  contains  granular 
matter.  The  cross-section  also  frequently  shows  strong  evi- 
dence of  stratification.  The  fibres  are  frequently  very  broad, 
and  at  these  parts  are  flat  and  ribbon- like  in  form,  but  are  never 
twisted  (see  Fig.  44). 

Miiller  gives  the  following  analysis  of  the  raw  fibre  of  samples 
of  both  China  grass  and  ramie: 


Constituent. 

China 
Grass. 

Ramie. 

Ash  

2  87 

C  6* 

W^ater  (hygroscopic) 

Aqueous  extract 

•W3 

6   A  7 

Kat  and  wax 

O    21 

Cellulose 

78    O7 

uoy 

66    22 

Intercellular  substances  and  pectin  

6.  10 

12.70 

3.  Hemp  is  a  name  applied  to  a  large  number  of  bast  fibres 
more  or  less  analogous  in  appearance  and  properties.*    Hemp 

*  Among  the  different  varieties  of  hemp  appearing  in  trade  may  be  enumerated 
the  following  (Dodge): 

Ambari  (or  brown)  hemp Hibiscus  cannabinus 

Bengal  (or  Bombay)  hemp Crotalaria  juncea 

Black-fellow's  hemp Commersonia  fraseri 

Bowstring  hemp  (Africa) Sansevieria  guineensis 

Bowstring  hemp  (India) S.  roxburghiana 

Bowstring  hemp  (Florida) S.  longiftora 

Calcutta  hemp Jute 

Cebu  hemp M usa  textilis 

Colorado  River  hemp Sesbania  macrocarpa 


192  THE    TEXTILE  FIBRES. 

proper,  or  the  so-called  common  hemp,  is  derived  from  the  bast 
of  Cannabis  sativa.  This  is  a  shrub  growing  from  6  to  15  ft.  in 
height,  and  though  originally  a  native  of  India  and  Persia,  it  is 
now  cultivated  in  nearly  all  the  temperate  and  tropical  countries 
of  the  world.  At  the  present  time  it  is  quite  extensively  grown 
in  America,  though  not  as  yet  in  sufficient  amount  to  satisfy  the 
home  consumption.  Russia  produces  an  enormous  quantity  of 
hemp ;  in  fact,  this  fibre  forms  one  of  that  country 's  staple  articles 
of  export.  Poland  is  also  a  large  producer.  French  hemp, 
though  not  grown  to  such  an  extent,  is  much  superior  in  quality 
to  that  from  either  Russia  or  Poland,  it  being  fine,  white,  and 
lustrous.  Italian  hemp  is  also  of  a  very  high  grade.  In  India 
hemp  is  not  grown  so  much  for  its  fibre  as  for  the  narcotic 
products  obtained.  Japanese  hemp  is  of  excellent  quality,  and 
appears  in  trade  in  the  form  of  very  thin  ribbons,  smooth  and 
glossy,  of  a  light  straw  color,  and  the  frayed  ends  showing  a  fibre 
of  exceeding  fineness.  Hemp  appears  to  have  been  the  oldest 
textile  fibre  used  in  Japan. 

Cretan  hemp Datisca  cannabina 

Cuban  hemp Furcraa  cubensis 

False  hemp  (American) Rhus  typhina 

False  sisal  hemp Agave  decipiens 

Giant  hemp  (China) Cannabis  gigantia 

Hayti  hemp Agave  fcetida 

Ife  hemp Sansevieria  cylindrica 

Indian  hemp Apocynum  cannabinum 

Jubbulpore  hemp  (Madras) Crotalaria  tenni/olia 

Manila  hemp Mnsa  textilis 

New  Zealand  hemp  (or  flax) Phormium  tenax^ 

Pangane  hemp Sansevieria  kirkii 

Pita  hemp Yucca  spp. 

Pua  hemp  (India) Maoutia  pnya 

Queensland  hemp Sida  retusa 

Rangoon  hemp Laportea  gigas 

Roselle  hemp Hibiscus  sabdariffa 

Sisal  hemp Agave  rigida 

Sunn  hemp Crotalaria  juncea 

Swedish  hemp Urtica  dioica 

Tampico  hemp Agave  hrtrr<icnntha 

Water  hemp Kupatorium  cannabinum 

Wild  hemp Maoutia  puya 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.       193 


The  hemp  fibre  is  obtained  from  the  plant  by  a  process  of 
retting  similar  to  that  employed  for  flax.  The  method  of  dew- 
retting  is  chiefly  used;  that  is,  the  stalks  are  spread  out  in  the 
fields  until  the  action  of  the  elements  causes  the  woody  tissue 
and  gums  enclosing  the  fibres  to  decompose.  Retting  in  pools 


FIG.  41. — Cross-section  of  Jute-straw.     (Cross  &  Bevan.) 

Showing  transverse  section  of  portion  of  bast  only,  giving  the  anatomy  of  the 
fibrous  tissue,  the  form  of  the  bast-cells,  and  the  thickening  of  the  cell-walls. 

of  water  has  been  practised  to  a  slight  extent,  but  evidently  not 
with  much  success.  It  is  said  that  100  kilos  of  raw  hemp  furnish 
25  kilos  of  raw  fibre  or  filasse;  and  100  kilos  of  the  latter  yield 
65  kilos  of  combed  filasse  and  32  kilos  of  tow. 

The  seed  of  the  hemp. plant,  like  that  from  flax,  is  also  utilize^ — 
for  the  oil  it  contains;    100  kilos  of  seed  furnish  27  kilos  of  oil. 


194 


THE   TEXTILE  FIBRES. 


So  this  forms  an  extensive  and  important  by-product  in  the  culti- 
vation of  hemp. 

Under  the  microscope  the  hemp  fibre  is  seen  to  consist  of 
cell  elements  which  are  unusually  long,  averaging  about  20  mm.  in 
length,  but  varying  from  5  to  55  mm.  The  diameter,  however, 
is  very  small,  averaging  22  //,  and  varying  from  1 6  to  50  /*.  Hence 
the  ratio  between  the  length  and  diameter  is  about  1000.  The 


FIG.  42.— Ramie  Fibre.     (Hohnel.) 

v,  swollen  displacements;   r,  fissures;   e,  point  or  end;   q,  cross-sections;   it  inner 
layers  of  fibre- wall;  /,  lumen;  sch,  stratifications. 

fibre  is  rather  uneven  in  its  diameter,  and  has  occasional  attach- 
ments of  fragmentary  lignified  tissue.  In  its  linear  structure  the 
fibre  exhibits  frequent  joints,  longitudinal  fractures,  and  swollen 
fissures.  The  lumen  is  usually  broad,  but  towards  the  end  of 
the  fibre  it  becomes  like  a  line  (see  Fig.  45.)  It  shows  scarcely 
any  contents.  The  ends  of  the  filaments  are  blunt  and  very 
thick-walled,  and  often  possess  lateral  branches.  The  cross- 
section  generally  shows  a  group  of  cells  which  nearly  always  have 
rounded  edges  and  are  not  so  sharp-angled  and  polygonal  as  in 


JUTE,   RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.       195 

the  case  of  jute.  There  is  alscTa  median  layer  between  the  cells, 
which  is  evidenced  by  it  turning  yellow  on  treatment  with  iodin 
and  sulphuric  acid.  In  the  section  the  lumen  appears  irregular 
and  flattened,  and  does  not  show  any  contents.  The  cell-walls 
frequently  exhibit  a  remarkable  stratification,  the  different  layers 


FIG.  43. — Cross-section  of  Ramie-straw.     (Cross  &  Bevan.) 

Showing  transverse  section  of  bast  region  only;    the  bast  fibres  are  to  be  distin- 
guished by  their  large  area  from  the  adjacent  tissue. 

yielding  a  variety  of  colors  on  treatment  with  iodin  and  sul- 
phuric acid  (see  Fig.  46). 

Hemp  is  somewhat  difficult  to  distinguish  microscopically  from 
flax;  but  the  two  may  readily  be  told  by  an  examination  of  the 
ends  of  the  fibres,  hemp  nearly  always  exhibiting  specimens  of 
forked  ends,  whereas  flax  never  has  this  peculiarity.  The  differ- 


196  THE    TEXTILE  FIBRES. 

ence  in  the  appearance  of  the  cross-sections  is  also  of  service  in 
discriminating  between  these  two  fibres.  Again,  the  parenchymous 
tissue  which  frequently  occurs  as  attached  fragments  to  hemp 
fibres  is  rich  in  star-shaped  crystals  of  calcium  oxalate,  and  this 
is  scarcely  ever  to  be  noticed  in  the  case  of  flax.  A  peculiarity  to 
be  noticed  in  the  examination  of  hemp  is  the  occasional  presence 
of  long  narrow  cells  filled  with  reddish  brown  matter,  insoluble  in 


^-~_   U      - 

FIG.  44.— Ramie  Fibre  (X 500). 
Showing  the  longitudinal  ridges  and  knotted-like  cross-markings  and  fissures. 

the  ordinary  solvents.  These  cells  occur  between  the  fibres  as 
well  as  in  the  bast,  and  probably  contain  tannin.  They  are  not 
to  be  found  in  flax.  The  behavior  of  isolated  hemp-cells  with 
ammoniacal  copper  oxide  solution  is  also  quite  characteristic ;  the 
cell  membrane  acquires  a  blue  to  a  bluish  green  color,  and  swells 
up  like  a  blister,  showing  sharply  defined  longitudinal  striations. 
The  inner  cell-wall  remains  undissolved  in  the  form  of  a  spirally 
wound  tube  contained  inside  the  strongly  swollen  mass  of  the 
fibre. 

The  hemp  fibre  is  not  composed  entirely  of  pure  cellulose,  as 
it  gives  a  green  coloration  with  anilin  sulphate,  and  iodin  and 
sulphuric  acid.  It  appears  to  be  a  mixture  of  cellulose  and  bas- 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.       197 

tose.     M tiller  gives  the  following  analysis  of  a  sample  of  best 
Italian  hemp: 

Per  Cent. 

Ash 0.82 

Water  (hygroscopic) 8.88 

Aqueous  extract 3-48 

Fat  and  wax o. 56 

Cellulose 77-77 

Intercellular  matter  and  pectin  bodies 9  •  31 

Hemp  is  principally  employed  for  the  manufacture  of  twine 
and  cordage,  for  which  its  great  strength  eminently  adapts  it ;  and 
besides,  it  is  a  very  durable  fibre,  and  is  not  rotted  by  water.  In 
this  respect  it  differs  very  essentially  from  jute.  It  is  seldom  used, 
however,  for  woven  textiles,  as  it  is  harsh  and  stiff,  and  not  suffi- 
ciently pliable  and  elastic.  It  also  possesses  a  rather  dark  brown 
color,  and  cannot  be  successfully  bleached  without  serious  injury 
to  the  quality  of  the  fibre. 

4.  Sunn  Hemp  is  the  bast  fibre  of  the  Crotalaria  juncea;  it 
is  also  known  by  the  names  of  Conkanee,  Indian,  Brown,  and 
Madras  hemp.  It  grows  abundantly  in  the  countries  of  southern 
Asia,  and  is  largely  used  in  the  manufacture  of  cordage.  It 
appears  to  have  been  one  of  the  earliest  fibres  mentioned  in 
Sanscrit  literature.  The  fibre  is  obtained  from  the  plant  by  a 
system  of  retting  very  similar  to  that  of  flax.  The  fibre  of  sunn 
hemp  is  of  a  better  quality  than  jute,  being  lighter  in  color,  of 
a  better  tensile  strength,  and  more  durable  to  exposure.  Dr. 
Wight  gives  the  following  table  for  the  strength  of  several  cordage 
fibres : 

Pounds 

Sunn  hemp 407 

Cotton  rope 346 

Hemp 290 

Coir 224 

In  appearance  sunn  hemp  is  very  similar  to  hemp,  both  to 
the  naked  eye  and  under  the  microscope.  The  essential  distinc- 
tion between  the  two  is  in  the  cross- section  (see  Fig.  47),  which 
shows  the  presence  of  a  very  thick  median  layer  of  lignin  between 


of 


198 


THE   TEXTILE  FIBRES. 


the   individual   cells.     The   lumen    in    the   cross-section   is   also 
usually  rather  thick,  and  often  contains  yellowish  matter,  differ- 


FIG.  45. — Fibres  of  Hemp  (X35o). 

Showing  longitudinal  fissures  and  numerous  transverse  cracks  and  jointed-like 

structure. 

ing  in  these  respects  from  hemp,  in  which  the  lumen  is  flat  and 
narrow  and  always  empty. 

Miiller  gives  the  following  analysis  of  raw  sunn  hemp : 

Per  Cent. 

Ash o.  61 

Water  (hygroscopic) 9 . 60 

Aqueous  extract 2.82 

Fat  and  wax o. 55 

Cellulose 80.01 

Pectin  bodies 6.41 

5.  Ambari  or  Gambo  Hemp  is  an  East  Indian  fibre  derived 
from  the  bast  of  Hibiscus  cannabinus.  The  fibre  when  care- 
fully prepared  is  from  5  to  6  feet  in  length ;  it  is  of  a  lighter  color 
than  hemp,  and  harsher.  Its  tensile  strength  is  somewhat  less 
than  that  of  sunn  hemp.  Like  the  latter  fibre,  it  is  principally 
used  for  cordage,  though  it  is  also  employed  in  India  for  the  man- 
ufacture of  a  coarse  canvas.  In  its  microscopic  characteristics 
ambari  hemp  is  very  similar  to  jute;  the  length  of  the  fibre  ele- 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES.      199 

ments  varies  from  2  to  6  mm.,  and  the  diameter  from  14  to  33  /*. 
The  median  layers  of  lignin  between  the  cells  are  broad,  and  are 
colored  much  darker  than  the  inner  layers  of  the  cell- wall  when 
treated  with  iodin  and  sulphuric  acid.  The  lumen  presents  the 
same  appearance  as  with  jute  (see  Fig.  48),  having  such  very 
marked  contractions,  that  in  places  it  is  discontinuous.  The  ends 
of  the  fibres  are  very  blunt  and  thick-walled. 

6.  New  Zealand  Flax  differs  somewhat  from  the  preceding 
fibres  in  that  it  is  derived,  not  from  the  bast,  but  from  the  leaves 
of  Phormium  tenax.  Botanically  these  are  known  as  sclerenchy- 
mous  fibres.  Apart,  however,  from  this  histological  difference, 
such  fibres  are  very  similar  in  general  structure  to  ordinary  bast 
fibres.  Phormium  tenax  is  a  native  of  New  Zealand,  but  is  also 
found  distributed  in  other  portions  of  Australasia;  it  has  been 
introduced  into  several  European  countries,  and  is  also  cultivated 
to  quite  an  extent  in  California.  The  fibre  of  New  Zealand  flax 
is  very  white  in  color,  is  soft  and  flexible,  and  possesses  a  high' 
lustre.  In  tenacity  the  fibre  appears  to  be  superior  to  either  flax 
or  hemp,  as  is  seen  by  the  following  comparative  figures  (Royle) : 

Pounds. 

New  Zealand  flax 23.7 

Flax 11.75 

Hemp 16. 75 

The  leaves  of  Phormium  tenax  reach  over  5  feet  in  length,  and 
the  fibre  is  separated  by  first  scraping  the  leaves  and  then  comb- 
ing out  the  separate  fibres.  No  process  of  retting  is  necessary,  as 
with  the  bast  fibres.  The  method  of  preparing  the  fibre,  how- 
ever, is  as  yet  very  unsatisfactory,  and  could  be  much  im- 
proved. The  amount  of  fibre  obtained  under  the  present  method 
of  operating  is  from  10  to  14  per  cent,  on  the  weight  of  the  leaves, 
although  the  latter  contain  as  much  as  20  per  cent,  of  fibre. 

In  their  microscopical  characteristics  the  fibres  of  New  Zea- 
land flax  are  remarkable  for  their  slight  adherence.  The  fibre  ele- 
ments are  5  to  15  mm.  in  length  and  10  to  20  jj.  in  diameter,  and 
the  ratio  of  the  length  to  the  breadth  is  about  550.  They  are 
very  regular  and  uniformly  thickened,  and  the  surface  is  smooth, 


200 


THE   TEXTILE  FIBRES. 


exhibiting  no  markings  or  jointed  sutures.  The  lumen  is  very 
apparent,  but  is  generally  narrower  than  the  cell- wall  and  is  very 
uniform  in  its  width.  The  ends  are  sharply  pointed  and  not 
divided.  The  cross-section  shows  rather  loosely  adhering  ele- 
ments (see  Fig.  49),  and  is  very  round  in  contour,  the  lumen  being 


FIG.  46.  FIG.  47. 

FIG.  46. — Hemp  Fibre  Showing  Stratification.     (Hohnel.) 

FlG.  47. — Sunn  Hemp.     (Hohnel.) 

L,  view  of  middle  portion;  v,  joints;  /,  lumen;   s,  pointed  ends;  q,  cross-sections; 
m,  outer  layer  of  fibre;  /,  inner  layers. 

either  round  or  oval,  and  is  empty.  No  median  layer  of  lignin  is 
apparent  between  the  elements,  though  the  fibres  themselves  are 
completely  lignified.  The  purified  fibre  of  New  Zealand  flax  is 
rather  difficult  to  distinguish  microscopically  from  aloe  hemp  or 
from  Sansevieria  fibre,  except  by  the  rounded  and  separated  cross- 
sections.  The  fibre  also  usually  contains  a  substance  derived  from 
the  sap  of  the  leaf  which  possesses  the  peculiarity  of  giving  a 
deep-red  color  with  concentrated  nitric  acid.  The  composition 
of  the  fibre  is  as  follows  (Church) : 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.      201 

Per  Cent. 

Ash o .  63 

Water n.6i 

Gum  (and  other  matter  soluble  in  water) 21. 99 

Fat i. 08 

Pectin  bodies i .  69 

Cellulose 63 .  oo 

New  Zealand  flax  is  principally  employed  in  the  making  of 
cordage  and  twine  and  floor-matting,  though  the  best  fibre  can 


FIG.  48. — Gambo  Hemp.     (Hohnel.) 

e,  ends  with  blunt  points  and  wide  lumen;  d,  lateral  branch;  /,  longitudinal  cut- 
ting, with  v,  interruptions  in  lumen;  q,  cross-sections,  with  L,  small  lumen; 
m,  median  layers. 

also  be  woven  into  cloth  resembling  linen  duck.  It  has  been  used 
extensively  in  the  United  States  for  the  making  of  ' '  staff, ' '  being 
mixed  with  plaster  for  this  purpose.  The  chief  drawback  to  the 
fibre  of  New  Zealand  flax  is  its  poor  resistance  to  water. 

7.  Manila  Hemp  is  the  fibre  obtained  from  the  leaf-stalks  of 
the  Musa  textilis,  a  variety  of  plantain  which  is  a  native  of  the 


202  THE   TEXTILE  FIBRES. 

Philippine  Islands.  The  fibre  is  white  and  lustrous  in  appear- 
ance, light  and  stiff  in  handle,  and  easily  separated.  It  is  also  a 
very  strong  fibre,  and  of  great  durability.  In  the  Philippines  it 
is  known  as  abaca.  The  coarser  fibres  are  used  for  the  manu- 
facture of  cordage,  for  which  purpose  it  is  eminently  suited  on 
account  of  its  great  strength.  The  relative  strengths  of  rope  made 
from  English  hemp  and  that  made  from  Manila  hemp  are  about 
10  to  12  respectively.  The  finer  fibres,  which  require  to  be 
selected  and  carefully  prepared,  are  woven  into  a  very  high  grade 
of  muslin,  which  brings  a  good  price,  even  in  Manila.  Under  the 
microscope  Manila  hemp  shows  fibre  elements  of  3  to  12  mm.  in 
length,  and  16  to  32  /JL  in  width,  the  ratio  of  the  length  to  the 
diameter  being  about  250.  The  bundles  of  fibres  are  very  large, 
but  by  treatment  with  an  alkaline  bath  are  easily  separated  into 
smooth,  even  fibres.  The  fibres  are  very  uniform  in  diameter,  are 
lustrous,  and  are  rather  thin-walled.  The  lumen  is  large  and 
distinct,  but  otherwise  the  fibre  does  not  exhibit  any  markings. 
The  cross-sections  are  irregularly  round  or  oval  in  shape,  and  the 
lumen  in  the  section  is  open  and  quite  large  and  distinct  (see 
Fig.  50).  The  fibre-bundles  frequently  show  a  series  of  peculiar, 
thick,  strongly  silicified  plates,  known  as  stegmata.  Lengthwise 
these  appear  quadrilateral  and  solid,  and  have  serrated  edges  and 
a  round,  bright  spot  in  the  centre.  The  stegmata  may  be  best 
observed  after  macerating  the  fibre-bundles  in  chromic  acid  solu- 
tion; they  are  about  30  /*  in  length.  On  extracting  the  fibre  with 
nitric  acid,  then  igniting,  and  adding  dilute  acid  to  the  ash  so 
obtained,  the  stegmata  will  appear  in  the  form  of  a  string  of  pearls, 
frequently  in  long  chains  with  sausage-like  links,  a  very  peculiar 
and  characteristic  appearance.  The  lumen  often  contains  a 
yellowish  substance,  but  no  distinct  median  layer  is  perceptible 
between  the  fibres.  Manila  hemp  is  a  lignified  fibre,  and  gives 
a  yellow  color  with  anilin  sulphate;  iodin  and  sulphuric  acid  give 
a  golden-yellow  to  a  green  color;  ammoniacal  copper  oxide  causes 
a  blue  coloration  and  a  slight  swelling.*  According  to  Miiller  the 
composition  of  Manila  hemp  is  as  follows: 

*  Besides  the  Musa  textilis,  the  fibre  from  the  following  varieties  is  also  utilized: 
Musa  paradisiaca,  M.  sapientium,  and  .17.  mindanensis  from  India  and  islands 
in  the  Pacific  Ocean;  M.  cavendishii  from  China;  M.  cusete  from  Africa. 


JUTE,  RAMIE,  HEMP,   AND  MINOR   VEGETABLE  FIBRES.      203 

Per  Cent. 

Ash i .  02 

Water n  .85 

Aqueous  extract o .  97 

Fat  and  wax o .  63 

Cellulose 64. 72 

Intrusting  and  pectin  matters 21 .83 

8.  Sisal  Hemp  is  the  fibre  obtained  from  the  leaves  of  the 
Agave  rigada,  a  native  of  Central  America;  it  is  also  grown  in  the 
islands  of  the  West  Indies  and  in  Florida.  The  fibre  has  a  light 
yellowish  color,  and  is  very  straight  and  smooth;  it  is  principally 
used  for  making  cordage,  for  which  purpose  it  is  quite  valuable, 
as  it  is  second  only  to  Manila  hemp  in  tensile  strength.  The  fibre 
is  easily  separated  from  the  leaf,  and  does  not  require  a  retting 
process.  In  their  microscopical  appearance  the  fibre-bundles 
often  show  an  interlaced  formation  with  a  peculiar  spiral  thick- 
ening. The  fibre  elements  are  1.5  to  4  mm.  in  length,  and  20 
to  32  fj.  in  breadth,  the  ratio  of  the  length  to  the  diameter  being 
about  100.  They  are  usually  quite  stiff  in  texture,  and  show  a 
remarkable  broadening  towards  the  middle.  The  width  of  the 
lumen  is  frequently  greater  than  that  of  the  cell-wall.  The  ends 
are  broad,  blunt,  and  thick,  but  seldom  forked.  The  cross-sec- 
tions are  colored  yellow  by  iodin  and  sulphuric  acid,  and  show  no 
evidence  of  a  median  layer  between  the  elements.  The  sections 
are  polygonal  in  outline,  but  often  have  rounded  edges,  and  the 
bundles  are  usually  close  together.  The  lumen  in  the  cross-sec- 
tion is  large,  and  polygonal  in  shape,  though  the  edges  of  the 
lumen  are  more  rounded  than  those  of  the  walls.  The  ash  ob- 
tained from  the  ignition  of  the  fibre  shows  the  presence  of  glisten- 
ing crystals  of  calcium  carbonate,  which  are  derived  from  the 
original  crystals  of  calcium  oxalate  to  be  found  clinging  to  the 
fibre-bundles.  They  are  usually  in  longitudinal  series,  about 
0.5  mm.  long,  and  taper  off  at  the  ends  to  a  chisel  shape,  resem- 
bling a  thick  needle  in  form,  but  having  a  quadrilateral  cross- 
section. 

9.  Aloe  Fibre,  or  Mauritius  hemp,  is  obtained  from  the  leaf  of 
various  species  of  aloe  plants,  growing  in  tropical  climates.  This 
fibre  is  often  confounded  with  that  of  the  Agave  americana,  but 


204 


THE   TEXTILE  FIBRES. 


it  is  of  different  origin.  Aloe  fibre,  however,  is  very  similar  to 
Sansevieria  fibre,  and  is  hardly  to  be  distinguished  from  it  in 
either  physical  or  microscopic  appearance.  The  fibre  elements 
are  1.3  to  3.7  mm.  in  length,  and  15  to  24  /z  in  breadth.  Although 


FIG.  49. — New  Zealand  Flax. 
P,  view  of  pointed  ends;  L,  view  of  middle  portion;  S,  cross-sections. 

uniformly  broad,  the  cell-wall  is  thin.  The  fibres  are  usually 
cylindrical  and  not  flattened;  they  show  occasional  fissure-like 
pores  (see  Fig.  51).  The  cross-sections  are  polygonal,  with  slightly 
rounded  edges.  The  lumen  is  usually  somewhat  broader  than 
the  walls,  and  in  the  cross-section  is  polygonal,  with  rounded  sides. 
In  the  Sansevieria  fibre  the  lumen  in  the  cross-section  is  usually 
larger,  and  the  cell- walls  consequently  thinner;  furthermore  the 
lumen  has  a  sharp-edged,  polygonal  form  (see  Fig.  51). 

10.  Pita  Fibre  is  obtained  from  the  leaf  of  the  Agave  americana, 
or  century  plant;  it  is  also  known  as  aloe  fibre.  The  fibre  is 
white  to  pale  straw  in  color,  is  stiff  and  short,  has  a  rather 
thin  wall,  and  furthermore  is  liable  to  rot.  The  fibres  have  a 
distinctive  wavy  appearance,  and  another  peculiarity  is  its  great 
elasticity.  According  to  Royle,  Indian  pita  has  been  found 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.      205 


FIG.  50.— Manila  Hemp.     (Hohnel.) 

q,  cross-sections;  /,  lumen  without  contents;  /,  lumen  containing  granular  mat- 
ter; a,  silicious  skeleton  of  the  stegmata;  b,  rows  of  stegmata,  flat  side;  c, 
the  same,  narrow  side. 


A. 


B. 


FIG.  51.— Aloe  Fibre.     (Hohnel.) 

A,  from  Aloe  speciosus;  B,  from  Sansevieria.     e,  ends;   /,  longitudinal  view; 
q,  cross-sections;    r,  fissure-like  pores  in  cell -walls. 


2o6  THE   TEXTILE  FIBRES. 

superior  in  strength  to  either  coir,  jute,  or  sunn  hemp,  the  break- 
ing strain  on  similar  ropes  made  of  these  materials  being  as 
follows: 

Pounds. 

Pita 2519 

Coir 2175 

Jute 2456 

Sunn  hemp 2269 

Russian  hemp  and  pita,  on  comparison,  gave  a  relative  strength 
of  16  to  27.  Besides  its  use  as  a  cordage  fibre,  pita  is  also  em- 
ployed for  the  making  of  a  very  delicate  and  beautiful  lace  known 
as  Fayal.  In  its  microscopical  characteristics  pita  is  very  sim- 
ilar to  sisal  hemp. 

11.  Pineapple  Fibre,  or  Silk  Grass,  is  obtained  from  Ananas 
saliva,  or  pineapple  plant.     This  fibre  has  great  durability  and  is 
unaffected  by  water.     It  is  very  fine  in  staple  and  highly  lustrous, 
and  is  white,  soft,  and  flexible.     It  is  usedjn  the  manufacture  of 
the  celebrated  pina  cloth  in  the  Philippine  Islands.     According 
to  Taylor,  a  specimen  of  this  fibre  was  subdivided  to  one  ten- 
thousandth  of  an  inch  in  thickness,  and  was  considered  to  be  the 
most  delicate  in  structure  of  any  known  vegetable  fibre.     Micro- 
scopically it  is  distinguished  from  all  other  leaf  fibres,  in  fact,  by 
the  extreme  fineness  of  its  fibre  elements.     These  are  3  to  9  mm. 
in  length  and  4  to  8  //  in  thickness.     The  lumen  is  very  narrow 
and  appears  like  a  line.     The  cross- sections  are  polygonal  in  out- 
line and  frequently  flattened.     The  sections  for  mcompact  groups 
which  are  often  crescent-shaped,   and  are  enclosed  in  a  thick 
median  layer  of  lignified  tissue. 

12.  Coir  Fibre  is  obtained  from  the  fibrous  shell  of  the  cocoa- 
nut.     The  fibre  occurs  in  the  form  of  large,  stiff,  and  very  elastic 
filaments,  each  individual  of  which  is  round,  smooth,  and  some- 
what   resembling  horsehair.      It  possesses    remarkable   tenacity 
and  curls  easily.     In  color  it  is  cinnamon-brown.      It  possesses 
marked  microscopical  characteristics;   the  fibre  elements  are  short 
and  stiff,  being  0.4  to  i  mm.  in  length  and  12  to  24  jj.  in  diameter; 
the  ratio  of  the  length  to  the  thickness  is  only  35.     The  cell-wall 
is  thick,  but  rather  irregularly  so,  in  consequence  of  which  the 
lumen  has  an  irregular  outline,  resembling  indentations  (see  Fig. 


JUTE,  RAMIE,  HEMP,  AND  MINOR   VEGETABLE  FIBRES.      207 

52).  The  points  terminate  abruptly  and  are  not  sharp,  and  there 
appear  to  be  a  large  number  of  pore- canals  penetrating  the  cell- 
wall.  On  the  external  surface  the  fibre-bundles  are  occasionally 
covered  with  small  lens- shaped,  silicified  stegmata,  about  15  ,«  in 
breadth.  These  stegmata  fuse  together  on  ignition,  giving  a  blis- 
ter on  the  ash.  If  the  fibre  is  boiled  with  nitric  acid  previous  to 
its  ignition,  the  stegmata  then  appear  in  the  ash  like  yeast- cells, 


FIG.  52.— Coir  Fibre. 
s,  serrations  in  wall  of  lumen;  p,  pores  in  wall;  si,  silicious  skeleton  from  stegmata. 

hanging  together  in  the  form  of  round,  silicious  skeletons.  The 
cross- section  of  the  fibre  is  oval  in  shape  and  yellowish  brown  in 
color,  and  enclosed  in  a  network  of  median  layers.  Coir  fibre  is 
employed  in  the  South  seas  instead  of  oakum  for  caulking  vessels, 
and  it  is  claimed  that  it  will  never  rot.  The  principal  use  for 
coir,  however,  is  for  cordage  and  matting.  For  cable-making  it 
is  said  to  be  superior  to  all  other  fibres  on  account  of  its  lightness 
and  great  elasticity.  Wright  gives  the  following  tests  on  various 
cordage: 

Pounds. 

Hemp 190 

Coir 224 

Bowstring  hemp 316 


CHAPTER  XVI. 

QUALITATIVE  ANALYSIS  OF  THE  TEXTILE  FIBRES. 

1.  IN    a    commercial    examination   of    manufactured    yarns, 
fabrics,  etc.,  it  will  only  be  necessary  to  distinguish  between  wool, 
silk,    cotton,   linen,   jute,  hemp,  and   ramie.     Under  wool  must 
also  be  included  analogous  animal  hairs,  such  as  mohair,  cash- 
mere, etc.     Other  animal  fibres,  such  as  cow-hair  and  horsehair, 
may  easily  be  distinguished  even  by  the  naked  eye.     Of  course 
there  are  numerous  other  fibres  of  vegetable  origin  which  are 
employed  more  or  less  for  textile  materials,  but  either  they  are 
not  liable  to  occur  in  conjunction  with  wool,  or  they  may  be  readily 
distinguished  from  the  latter  without  requiring  a  special  exami- 
nation. 

The  best  method  of  distinguishing  qualitatively  between  the 
various  fibres  above  mentioned  is  by  the  use  of  the  microscope, 
whereby  their  characteristic  physical  appearance  may  be  readily 
observed.  Each  of  the  fibres  in  question  presents  certain  micro- 
scopical peculiarities,  so  that  no  difficulty  is  encountered  in  dis- 
tinguishing between  them.  The  difference  in  the  microscopical 
appearance  of  these  fibres  may  be  comparatively  observed  by 
reference  to  the  figures  given  in  the  preceding  pages. 

2.  Qualitative    Tests. — A   rough  physical   test   to   distinguish 
between  animal  and  vegetable  fibres  is  to  burn  them  in  a  flame. 
Vegetable  fibres  burn  very  readily  and  without  producing  any 
disagreeable  odor;    animal  fibres,  on  the  other  hand,  burn  with 
some  difficulty  and  emit  a  disagreeable  empyreumatic  odor  re- 
sembling that  of  burning  feathers.     The  burnt  end  of  the  fibre 
is  also  characteristic,  vegetable  fibres  burning  off  sharply  at  the 
end,  whereas  animal  fibres  fuse  to  a  rounded,  bead-like  end. 

208 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         209 


Tables  I  and  II  exhibit  the  characteristic  chemical  reac- 
tions of  the  principal  fibres,  and  by  suitably  employing  these 
tests  the  various  fibres  may  be  easily  distinguished  from  one 
another. 

TABLE  I. 


Test. 

Wool. 

Silk. 

Linen. 

Cotton. 

DYESTUFF  TESTS. 
Madder  tincture  

Nil 
Scarlet 
Red 
Dyed 
Nil 

Partly  diss. 
Nil 
Violet  to  brown 
Red  to  brown 
Black 
Black  ppt. 
Swells  only 
Undissolved 

Nil 
Scarlet 
Red 
Dyed 
Nil 

Dissolves 
Nil 
Nil 
Nil 
Nil 
No  ppt. 
Nil 
Dissolves 

Orange 
Violet 
Nil 
Nil 
Dyed 

Yellow 
Light  red 
Nil 
Nil 
Dyed 

Cochineal  tincture  

Fuchsin  

Acid  dyes  in  general.  .  .  . 
Mikado  yellow 

ACTION  OF  VARIOUS 
SALTS. 
Zinc  chloride 

Fibre  undiss.,  yellow  color 
Black  color 
Nil 
Nil 
Nil 
Nil 
Swells  and  partly  dissolves 
Undissolved 

Stannic  chloride       ... 

Silver  nitrate  
Mercury  nitrate(Millon's) 
Cupric  or  ferric  sulphate  . 
Sodium  plum  bite  

Ammoniacal  copper  oxide 
Ammoniacal  nickel  oxide 

The  reagents  employed  for  the  tests  in  the  tables   may   be 
prepared  as  follows: 

(1)  Madder  Tincture. — Extract  i  gm.  of  ground  madder  with 
50  c.c.  of  alcohol,  and  filter  from  Undissolved  matter. 

(2)  Cochineal  Tincture. — This  is  made  in  the  same  manner 
as  the  above,  using  i  gm.  of  ground  cochineal  insects. 

(3)  Fuchsin  Solution. — Dissolve  i  gm.  of  fuchsin  (magenta) 
in  100  c.c.  of  water,  then  add  caustic  soda  solution  drop  by  drop 
until  the  fuchsin  solution  is  decolorized;   filter  and  preserve  in  a 
well-stoppered  bottle.     In   applying  the   test  with   this   reagent, 
the  mixed  fibres  are  treated  with  the  hot  solution,  then  well  rinsed, 
when   the   animal  fibres  will    be  dyed  red,  the  vegetable  fibres 
remaining  colorless. 

(4)  Zinc    Chloride    Solution. — Dissolve    1000    gms.    of   /sine 
chloride  in  850  c.c.  of  water,  and   add  40  gms.  of  zinc  oxide, 
heating  until  complete  solution  is  effected. 

(5)  Stannic  Chloride  Solution. — This  may  be  prepared  by  dis- 
solving 15  gms.  of  stannous  chloride  (SnCL,)  in  15  c.c.  of  concen- 


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QUALITATIVE  ANALYSIS   OF   THE    TEXTILE  FIBRES.         211 

trated  hydrochloric  acid,  then  gradually  adding  3  gms.  of  pow- 
dered potassium  chlorate  (KC1O3).  Dilute  to  100  c.c.  with 
water. 

(6)  Silver  Nitrate  Solution. — 5  gms.  of  silver  nitrate  (AgNO8) 
are  dissolved  in  100  c.c.  of  water,  and  preserved  in  an  amber- 
colored  bottle. 

(.7)  Mercury  Nitrate,  Milton's  Reagent. — Dissolve  10  gms.  of 
mercury  in  25  c.c.  of  nitric  acid  diluted  with  25  c.c.  of  water  at  a 
luke-warm  temperature.  Mix  this  solution  with  one  of  10  gms. 
of  mercury  in  20  c.c.  of  fuming  nitric  acid. 

(8)  Copper  Sulphate  or  Ferric  Sulphate. — Dissolve  5  gms.  of 
these  salts  respectively  in  100  c.c.  of  water. 

(9)  Sodium  Plumbite. — Dissolve   5   gms.   of  caustic  soda  in 
100  c.c.  of  water  and  add  5  gms.  of  litharge  (PbO),  and  boil  until 
dissolved. 

(10)  Ammoniacal  Copper  Oxide,  Schweitzer's  Reagent. — Dis- 
solve 5  gms.  of  copper  sulphate  in  100  c.c.  of  boiling  water,  add 
caustic  soda  solution  till  the  copper  compound  is  completely  pre- 
cipitated, wash  the  precipitate  of  copper  hydrate  well,  then  dis- 
solve in  the  least  quantity  of  ammonia  water.     This  gives  a  deep 
blue  solution. 

(n)  Ammoniacal  Nickel  Oxide. — Dissolve  5  gms.  of  nickel 
sulphate  in  100  c.c.  of  water  and  add  a  solution  of  caustic  soda 
until  the  nickel  hydrate  is  completely  precipitated;  wash  the  pre- 
cipitate well  and  dissolve  in  25  c.c.  of  concentrated  ammonia  and 
25  c.c.  of  water.  This  solution  dissolves  silk  almost  immedi- 
ately, but  reduces  the  weight  of  vegetable  fibres  only  about  0.45 
per  cent.,  and  of  wool  only  0.33  per  cent. 

(12)  Caustic  Potash  or  Caustic  Soda. — Dissolve  10  gms.  of 
the  caustic  alkali  in  100  c.c.  of  water  and  filter. 

(13)  Sodium  Nitroprusside. — Dissolve  2   gms.  of  the  salt  in 
100  c.c.  of  water. 

(14)  Lead  Acetate. — Dissolve  5  gms.  of  lead  acetate  crystals 
(sugar  of  lead)  in  100  c.c.  of  water. 

(15)  Sulphuric  and  Nitric  Acids. — The  commercial  concen- 
trated acids  are  employed. 

(16)  Chlorin  Water. — Water  is    saturated   with    chlorin    gas 


212  THE   TEXTILE  FIBRES. 

obtained  by  acting  on  pyrolusite  (MnO2)  with  hydrochloric  acid. 
The  solution  should  be  preserved  in  amber- colored  bottles. 

(17)  lodin  Solution. — Dissolve  3  gms.  of  potassium  iodide  in  60 
c.c.  of  water,  and  add  i  gm.  of  iodin.     Dilute  this  solution,  before 
using,  with  10  parts  of  water.     When  the  reaction  is  employed 
in  connection  with  sulphuric  acid,  the  latter  consists  of  3  parts  of 
concentrated  sulphuric  acid,  i  part  of  water,  and  3  parts  of  gly- 
cerin.     The  glycerin  has  the  effect  of  preventing  injury  to  the 
fibres,  and  at  the  same  time  brings  out  certain  details  of  the 
structure  when  the  fibres  have  previously  absorbed  the   iodin. 
The  fibres  are  moistened  first  with  the  iodin  solution  and  then 
with  the  sulphuric  acid  solution. 

(18)  Picric  Acid  Solution. — Dissolve  0.5  gm.  of  picric  acid  in 
100  c.c.  of  water. 

A  delicate  reaction  *  for  detecting  the  presence  of  vegetable 
fibres  in  wool  is  the  following:  The  sample  of  material  under 
examination  is  well  boiled  with  water  to  remove  any  finishing 
materials  that  might  be  present  and  interfere  with  the  reaction. 
Then  a  small  portion  of  the  sample  is  put  in  a  test-tube  with  i  c.c. 
of  water  and  2  drops  of  an  alcoholic  solution  of  alpha- naphthol 
and  about  i  c.c.  of  concentrated  sulphuric  acid.  If  vegetable 
fibres  are  present  they  will  be  dissolved  and  the  liquid  will  acquire 
a  deep  violet  color  when  shaken;  the  animal  fibres  only  give  a 
yellow  to  reddish  brown  coloration  but  no  violet  tint.  If  thymol 
Is  used  instead  of  alpha-naphthol,  a  beautiful  red  coloration  will 
be  produced  in  the  presence  of  vegetable  fibres.  Cross  and 
Bevan  have  devised  a  delicate  test  which  is  serviceable  for  detect- 
ing the  presence  of  vegetable  fibres  in  fabrics:  the  sample  of  the 
cloth  is  immersed  in  a  solution  of  ferric  chloride  and  potassium 
ferrocyanide,  when  any  vegetable  fibre  present  will  be  colored 
blue. 

Lieberman  gives  a  test  to  distinguish  between  animal  and 
vegetable  fibres  as  follows:  The  fibres  are  boiled  with  a  solution 
of  magenta  which  has  previously  been  decolorized  by  the  addi- 
tion of  just  sufficient  caustic  soda;  then  they  are  well  washed  and 

*  Molisch,  Dingl.  Polyt.  Jour.,  1886. 


QUALITATIVE  ANALYSIS   OF  THE   TEXTILE  FIBRES.         213 

placed  in  water  slightly  acidulated  with  acetic  acid.  If  the  fibres 
are  of  animal  origin  they  will  be  colored  a  deep  pink,  whereas 
cotton  and  linen  fibres  will  be  unaffected. 

Both  this  reaction  and  the  one  with  picric  acid  (see  Table  II) 
are  convenient  to  use  when  it  is  desirable  to  render  visible  the 
animal  fibres  in  a  mixed  yarn  or  fabric.  In  case  of  a  mixture  of 
wool  and  silk  fibres,  the  wool  may  readily  be  shown  by  placing 
the  sample  in  a  very  dilute  boiling  solution  of  caustic  soda  con- 
taining a  few  drops  of  lead  acetate  solution.  Any  wool  present 
will  be  turned  brown  by  this  treatment,  due  to  the  formation  of 
lead  sulphide  from  the  sulphur  which  forms  a  constituent  of  this 
fibre.  Silk  (and  also  cotton  or  other  vegetable  fibre)  will  not  be 
colored.  In  this  test,  of  course,  it  will  be  necessary  that  the 
sample  is  undyed,  or,  at  least,  that  all  coloring-matters  originally 
present  be  completely  removed. 

Allen  *  summarizes  in  the  table  on  page  214  the  reactions  to 
distinguish  silk  qualitatively  from  other  fibres. 

3.  Distinction  between  Cotton  and  Linen. — As  it  is  often 
desirable  to  discriminate  between  these  two  fibres,  the  following 
tests,  as  suggested  by  various  authorities,  are  given: 

(1)  The  fibre  is  burnt: 
Cotton — burnt  end  tufted. 
Linen — burnt  end  rounded. 

(2)  The  fibre  is  immersed  in  concentrated  sulphuric  acid  for 
two  minutes,  washed  well  with  water,  then  with  dilute  ammonia 
water,  and  dried : 

Cotton — forms  a  gelatinous  mass  soluble  in  water. 
Linen — the  fibre  is  unaltered. 

(3)  The  fibre  is  treated  with  an  alcoholic  solution  of  madder 
for  fifteen  minutes : 

Cotton — becomes  bright  yellow  in  color. 
Linen — becomes  dull  orange-yellow  in  color. 

(4)  The  fibre  is  treated  with  an  alcoholic  solution  of  cochineal 
for  fifteen  minutes : 

Cotton — becomes  bright  red  in  color. 
Linen — becomes  violet- red  in  color. 

*  Commer.  Org.  Anal.,  vol.  iv.  518. 


THE    TEXTILE  FIBRES. 


Test. 

Silk,  Wool,  Fur,  or  Hair. 

Cotton  or  Linen. 

Heated  in  a  small  test- 
tube 

Brittle,    carbonaceous    residue, 
and  odor  of   burnt  feathers. 
Gases  and    condensed  mois- 
ture alkaline  to  litmus 

Charring  and  smell  of 
burning  wood.  Gases 
and  condensed  mois- 
ture acid  to  litmus 

Boiled  on  a  saturated  aque- 
ous  solution    of   picric 
acid  and  rinsed  in  water 

Dyed  yellow 

Unchanged 

Boiled  with  Millon's  rea- 
gent (see  p.  210) 

Red  coloration 

No  change  of  color 

Treated  with  cold  nitric 
acid  (1.2  sp.  gr.) 

Colored  yellow 

No  change  of  color 

Moistened  with  dilute  hy- 
drochloric acid  and 
dried  at  100°  C. 

Unchanged 

Becomes  rotten 

Heated  to  boiling  with  hy- 
drochloric acid 

Silk. 

Wool,  Fur,  or 
Hair. 

Mostly  undissolved 

Dissolved 

Swells,  without 
at  once  dis- 
solving 

Boiled  with  a  cone,  solu- 
tion of  basic  zinc  chlo- 
ride (see  p.  208) 

Dissolved 

Unchanged 

Unchanged 

Treated  with  cold  Schweit- 
zer's reagent  (see  p.  210) 

Dissolved;  not 
precipita  ted 
by     addition 
of  salts 

U  n  d  i  ssolved  ; 
dissolves  on 
heating 

Dissolved  ;        solution 
precipitated  by  addi- 
tion of  salts 

Treated  in  the  cold  with 
10  per  cent,  caustic  soda 

Undissolved 

Dissolved 

Undissolved 

Boiled  with  a  2  per  cent, 
solution  of  caustic  soda 

Dissolved;  so- 
lution    not 
darkened  by 
lead  acetate; 
negative    re- 
action    with 
sodium  nitro- 
prusside 

Dissolved;  so- 
lution gives 
black  or 
brown  pre- 
cipitate with 
lead  acetate 
and  violet 
color  with 
sodium  nitro- 
prusside 

Unchanged 

Behavior  with  Molisch's 
test  (see  p.  211) 

Dissolved, 
with    little 
coloration 

U  n  d  i  ssolved, 
with  yellow 
or  brown  col- 
oration 

Dissolved,  with  deep 
violet  color 

QUALITATIVE  ANALYSIS  OF   THE   TEXTILE  FIBRES.         215 

(5)  The  fibre  is  immersed  in  olive  oil  or  glycerin,  after  pre- 
viously being  well  dried: 

Cotton — remains  opaque  and  white. 

Linen — becomes  translucent  by  reason  of  the  oil  rising  by 

capillary  action  between  the  individual  filaments 

of  the  fibres. 

(6)  The  fibre  is  treated     with  an  alcoholic  solution  of  rosolic 
acid,  and  then  with  a  concentrated  caustic  soda  solution : 

Cotton — remains  colorless. 
Linen — becomes  rose- red  in  color. 

(7)  The  fibre  is  treated  with  iodin  and  sulphuric  acid  solu- 
tions (see  p.  211): 

Cotton — becomes  pure  blue  in  color. 

Linen — gives  only  a  dull  blue  color.     This  test  is  satisfac- 
tory only  on  unbleached  linen. 

(8)  A  small  portion  of  the  sample  is  placed  in  a  solution  of 
equal  parts  of  water  and  caustic  potash ;  at  the  end  of  two  minutes 
the  sample  is  raised  with  a  glass  rod  and  placed  between  several 
thicknesses  of  filter-paper  to  remove  the  excess  of  water : 

Cotton — remains  white  or  is  a  pale,  clear  yellow  in  color. 
Linen — becomes  dark  yellow  in  color.     This  test  is  adapted 
only  for  white  goods. 

(9)  Kuhlmann  recommends  the  use  of  a  cold  concentrated 
solution  of  caustic   potash.    This   causes  unbleached   cotton  to 
shrink  and  curl  up,  and  to  become  gray  or  dirty  white  in  color; 
whereas  unbleached  linen  shrinks  more  than  cotton,  and  acquires 
a  yellowish  orange  color. 

(10)  The  fibres  are  immersed  in  a  saturated  solution  of  sugar 
and  common  salt,   and  dried.     The  separate  threads  are  then 
ignited : 

Cotton — leaves  a  black- colored  ash. 
Linen — leaves  a  gray-colored  ash. 

4.  Distinction  between  New  Zealand  Flax  (Phormium  tenax), 
Jute,  Hemp,  and  Linen. — The  following  series  of  tests  is  recom- 
mended to  distinguish  between  the  fibres  in  question: 

(i)  The  material  is  immersed  in  chlorin  water  for  one  min- 
ute, then  spread  on  a  porcelain  dish,  and  several  drops  of  ammo- 


216  THE    TEXTILE  FIBRES. 

nia  water  added.  New  Zealand  flax  and  jute  become  at  first 
bright  red  in  color,  which  afterwards  changes  to  dark  brown; 
linen  and  hemp  acquire  a  much  lighter  shade,  such  as  clear 
brown,  orange,  or  fawn.  This  method  is  very  good  for  yarn  or 
unbleached  cloth,  and  is  particularly  well  adapted  for  testing  sail- 
cloth. French  hemp  retted  in  stagnant  water  is  colored  a  much 
deeper  shade  than  the  same  kind  of  hemp  retted  in  running  water; 
in  either  case  the  color  is  much  darker  than  that  acquired  by 
linen.  For  testing  twine  this  method  is  said  to  give  excellent 
results,  but  in  bleached  material  the  difference  in  the  shades  pro- 
duced is  not  very  marked. 

(2)  To  test  bleached  material,   the  sample  is  immersed  for 
one  hour,  at  36°  C.,  in  nitric  acid  containing  nitrous  oxide.     New 
Zealand  flax  assumes  a  blood-red  color,  while  linen  or  hemp  is 
tinted  pale  yellow  or  rose,  according  to  the  method  by  which  it 
were  originally  retted. 

(3)  A  sample  of  the  material  is  heated  in  concentrated  hydro- 
chloric acid.     Hemp  and  linen  will  not  become  colored,  whereas 
New  Zealand   flax   becomes   yellow  at   a  temperature  of  30°  to 
40°  C.,  then  becomes  red,  brown,  and  finally  black. 

(4)  A  sample  of  the  material  is  treated  with  a  solution  of 
iodic  acid.     Hemp  and  linen  are  not  affected,  but  New  Zealand 
flax  acquires  a  rose- red  color. 

(5)  Jute  is  distinguished  from  New  Zealand  flax  by  soaking 
the  fibres  for  two  to  three  minutes  in  a  solution  of  iodin,  and 
then  rinsing  several  times  in  a  i  per  cent,  solution  of  sulphuric 
acid    to  remove  excess  of   iodin.     Jute  acquires  a  characteristic 
reddish  brown  color;    New  Zealand  flax  becomes   clear  yellow 
in  color;   hemp  acquires  a  light  yellow  color,  and  linen  a  blue 
color.     It  will  be  found  best  to  untwist  the  separate  threads  pre- 
vious to  this  treatment.     For  the  preparation  of  the  iodin  and 
sulphuric  acid  solutions,  see  p.  211. 

5.  Ligneous  Matter  (derived  from  woody  tissue)  may  be 
detected  in  admixture  with  other  fibres  in  the  following  manner: 

(i)  On  exposing  the  moistened  sample  to  the  action  of  chlorin 
or  bromin,  and  then  treating  it  with  a  neutral  solution  of  sodium 
sulphite,  a  purple  color  will  be  produced. 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         217 

(2)  If  the  sample  be  moistened  with  an  aqueous  solution  of 
anilin  sulphate,  an  intense  yellow  color  will  be  produced. 

(3)  If  the  sample  be  moistened  with  a  solution  of  phloro- 
glucinol  of  %  per  cent,  strength,  and  then  with  hydrochloric  acid, 
an  intense  violet-red  color  will  be  produced.     Solutions  of  resor- 
cinol,  orcinol,  and  pyrocatechol  act  in  a  similar  manner. 

(4)  Woody  fibre  when  boiled  in  a  solution  of  stannic  chloride 
containing  a  few  drops  of  pyrogallol  gives  a  fine  purple  color, 
which  is  easily  seen  under  a  magnifying-glass. 

6.  Goodale  gives  the  table  on  page  218,  presenting  reactions 
for  the  principal  bast  fibres. 

7.  Systematic   Analysis    of    Mixed    Fibres.  —  The    table   by 
Pinchon  (p.  219)  represents  an  attempt  to  give  a  systematic  qual- 
itative analysis  of  the  most  important  textile  fibres.    With  a  due 
degree  of  caution,  this  schematic  analysis  may  be  employed  with 
considerable  success,  though  confirmatory  tests  should  be  applied 
to   the   detection   of   each   fibre   indicated.     The   differentiation 
between  the  various  vegetable  fibres  given  is  especially  difficult. 

8.  Identification  of  Artificial  Silks. — Hassac   gives  the  table 
on  page  220,  presenting  systematic  tests  to  identify  the  different 
varieties  of  artificial  silks  or  forms  of  lustra-cellulose,  and  also 
the  distinction  between  these  latter  and  true  silk. 

9.  Distinction  between  True  Silk  and  Different  Varieties  of 
Wild  Silk. — True  silk  (from  Bombyx  mori)  rapidly  dissolves  (one- 
half  minute)  in  boiling  concentrated  hydrochloric  acid;    Senegal 
silk  (from  Faidherbia)  dissolves  in  a  somewhat  longer  time,  while 
yama-mai,   tussah,   and    cynthia    silks    require  a  much    longer 
time  for  complete  solution.     True  silk  is  also  rather  easily  solu- 
ble in  strong  caustic  potash  solution,  whereas  the  other  varieties 
of  silk  are  not.     The  most  approved  reagent,  however,  for  sepa- 
rating true  silk  from  the  wild  varieties  is  a  semi-saturated  solution 
of  chromic  acid,   prepared  by  dissolving  chromic  acid  in  cold 
water  to  the  point  of  saturation  and  then  adding  an  equal  volume 
of  water.     True  silk  is  completely  dissolved  on  boiling  in  this 
solution  for  one  minute,  whereas  wild  silk  remains  insoluble. 

Under  the  microscope  true  silk  can  readily  be  told  from  wild 
silks,  as  the  latter  fibres  are  broad  and  flat,  and  show  very  dis- 


218 


THE   TEXTILE  FIBRES 


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QUALITATIVE  ANALYSIS  OF   THE   TEXTILE  FIBRES.         219 


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220 


THE    TEXTILE  FIBRES. 


IDENTIFICATION  OF  ARTIFICIAL  SILKS. 


Reagent 

Natural  Silk. 

Collodion  Silk. 

Cellulose  Silk. 

Gelatin  Silk. 

Water 

No  change 

Swell  up;    addition  of   alcohol   or   glycerin 
causes  contraction  again 

Cone,  sulphuric 
acid 

Swells  rapidly 
and     d  i  s  - 
solves 

Gradually  be- 
comes thin- 
ner and  dis- 
solves 

Only  dissolves 
on  heating 

Acetic  acid 

— 

Slight    swell- 
ing 

Slight    swell- 
ing 

Dissolves  o  n 
boiling 

Half-saturated 
sol.  of  chromic 
acid 

Dissolves  slow- 

iy 

Dissolves  in  the  cold 

Diphenvlamin 
and    sulphuric 
acid 

— 

Blue  color 

— 

— 

Caustic  potash, 
40% 

Dissolves  with- 
out color 

Swell  without  dissolving,  but 
color  liquid  yellow 

Dissolves  rap- 
idly 

Ammoniacal  cop- 
per solution 

— 

Swells  quickly 
and         dis- 
solves 

Swells  slowly 
and     d  i  s  - 
solves 

Insoluble;  col- 
ors liquid 
violet 

Alkaline  copper 
glycerin  solu- 
tion 

Dissolves  im- 
mediately at 
80°  C.  tus- 
sah  silk  dis- 
solves in  one 
minute  o  n 
boiling 

Unchanged 

Unchanged 

Dissolves  o  n 
boiling 

lodin  in  potas- 
sium iodide 

— 

An  intense  red  color  which   disappears  on 
washing 

lodin  and  sul- 
phuric acid 

Yellow 

Deep    violet- 
blue 

Pure  blue 

Yellowish  t  o 
reddish 
brown 

lodin      in      zinc 
chloride 

Becomes  yel- 
low and  dis- 
integrates 

Blue-  violet 

Gray-blue  to 
gray-violet 

Becomes  yellow 
and  disinte- 
grates 

Ignition 

Odor  of  burnt 
feathers 

No  odor 

No  odor 

Odor  of  burnt 
feathers 

QUALITATIVE  ANALYSIS  OF   THE    TEXTILE  FIBRES.         221 

tinct  longitudinal  striations,  which  are  absent  in  true  silk.  Excep- 
tion must  perhaps  be  made  with  the  wild  silk  from  Saturnia 
spini,  which  can  scarcely  be  told  from  true  silk  by  a  micro- 
scopical examination.  With  regard  to  distinguishing  between 
the  different  varieties  of  wild  silks  themselves,  some  valuable 
information  may  be  gained  by  a  determination  of  their  relative 
diameters.  Hohnel  gives  the  following  values  for  the  greatest 
thickness  of  the  different  silks: 

True  silk  (Bombyx  mori) 20  to  25  fj. 

Senegal  silk        (Faidherbia  bauhini) 30  to  35  JJL 

Ailanthus  silk  (Attacus  cynthia) 40  to  50  fjL 

Yama-mai  silk  (Anthercea  yama-mai) 40  to  50  fj. 

Tussah  silk        (Bombyx  selene) 50  to  55  fJL 

Tussah  silk        (Bombyx  mylittd) 60  to  65  JJL 

According  to  Wiesner  and  Prasch,  the  breadths  of  the  single 
fibres  of  different  silks  are  as  follows: 

Ailanthus  silk 7  to  27,  mostly  14  fl 

Yama-mai  silk 10  to  45,  mostly  23  fj. 

Bombyx  mylitta 14  to  75,  mostly  42  ft 

Bombyx  selene 27  to  41,  mostly  34  jt/ 

Senegal  silk 12  to  34,  mostly  22  fi 

True  silk 9  to  21,  mostly  13  fjL 

True  silk,  ailanthus  silk,  and  Senegal  silk  do  not  show  any 
cross- marks,  or  only  very  faint  indications  of  such;  whereas  with 
tussah  silk  and  yama-mai  silk  the  cross-marks  are  very  distinct 
and  characteristic. 

The  microscopical  appearance  of  the  end  of  the  fibre  on  being 
torn  apart  also  serves  at  times  as  a  useful  means  of  distinguishing 
the  variety  of  silk;  true  silk,  tussah  silk,  and  yama-mai  silk 
show  scarcely  any  fraying  at  the  ends;  in  Senegal  silk  the  fraying 
is  very  noticeable  in  almost  every  fibre;  while  in  ailanthus  silk 
about  one-half  of  the  number  of  fibres  show  a  frayed  end.* 

*  Besides  the  wild  silks  mentioned  above,  there  are  a  few  others  of  lesser  im- 
portance, which  for  the  sake  of  completeness  are  herewith  described: 

i.  Saturnia  polyphemus,  a  North  American  variety;  consists  of  very  flat 
fibres,  with  large  air-canals  and  numerous  structural  filaments  separating  at  the 
edge  of  the  fibre;  coarse  lumps  of  adhering  sericin  are  frequent;  well-defined 


222  THE   TEXTILE  FIBRES. 

By  the  use  of  the  polariscopic  attachment  to  the  microscope, 
considerable  differences  can  be  observed  in  the  interference  colors 
displayed  by  the  different  varieties  of  silks.  It  is  best  to  conduct 
these  observations  under  a  magnification  of  30  to  50  diameters; 
and  as  the  silk  fibres  are  more  or  less  ovoid  in  section,  it  must  be 
borne  in  mind  that  the  same  fibre  will  give  a  different  color  phe- 
nomenon, depending  on  whether  it  is  viewed  from  the  narrow 
side  or  from  the  broad  side.  Hence,  to  obtain  trustworthy  results, 
the  appearance  of  the  same  side  only  of  the  fibres  should  be  com- 
pared. Also,  the  appearance  of  single  fibres  only,  and  not  of 
crossed  fibres,  should  be  taken.  Hohnel  gives  the  following 
description  of  the  appearance  of  the  different  silk  fibres  viewc-d 
in  polarized  light,  the  observations  being  made  with  a  dark  field, 
and  under  a  magnification  of  30  to  50  diameters: 

i.  True  silk:    (a)  broad  side,  very  lustrous,  of  a  bluish  or  yel 


cross-marks  are  also  frequent.      The  single  fibre  is  about  33^  in  width;    in  its 
polariscopic  appearance  these  fibres  very  much  resemble  ailanthus  silk. 

2.  Arryndia  ricini;    the  fibres  are   even   more  flattened  than  the   preceding, 
and  resemble  a  thin  band  or  ribbon;    large  air-canals  are  of  frequent  occurrence; 
striations  very  apparent;    the  sericin  layer  is  in  places  very  thin,  and  sometimes 
apparently  lacking  altogether.     The  double  fibre  is  about  45  to  55  fj.  in  width, 
and  4  to  6  fjL  thick.     At  the  edge  of  the  fibre  frayed  ends  of  structural  filaments 
are  often  apparent.     Cross-marks  are  rather  ill-defined,  but  of  frequent  occur- 
rence.    The  sericin  layer,  though  thin,  is  quite  uniformly  developed. 

3.  AnthercRa  pernyi  has  a  very  flat  fibre,  resembling  a  ribbon;    it  does  not 
fray  out  at  the  ends,  and  shows  scarcely  any  single  filaments.     The  double  fibre 
measures  60  to  80  fi  in  width  and  8  to  10  //  in  thickness.     Cross-marks  are  rather 
few  and  indistinct.     The  sericin  layer  is  very  thin,  and  in  general  hardly  noticeable. 
Moderately  sized  air-canals  are  present. 

4.  Saturnia  cecropia  occurs  in  Texas.     The  fibre  is  also  flat  and  ribbon-like 
in  form;   the  double  fibre  measures  60  to  90  fj.  in  width  and  10  to  15  ft  in  thickness; 
air-canals  are  frequent  and  large,  hence  the  fibre  usually  appears    rather  dark 
under  the  microscope.     The  cross-marks  are  very  distinct,   and  at  such   points 
the  fibre  is  much  broader.     The  fibre  is  usually  much  frayed  out  and  individual 
filaments  are  easily  distinguished.     The  sericin  layer  is  quite  thin  but  very  uni- 
form. 

5.  Attacus  lunula  has  fibres  which  are  not  so  flat  as  the  preceding.     The 
double  fibre  is  25  to  35/1  in  width  and  12  to  18  JA  in  thickness.     The  air-canals 
are  fine  and  delicate;    and  the  fibre  shows  but  a  slight  degree  of  fraying.     The 
sericin  layer  is  very  thin  and  finely  granulated  on  the  surface;    in  places,  it  has 
the  form  of  irregular  shreds.     The  fibre  as  a  whole  has  a  brownish  yellow  appear- 
ance due  to  the  ochre-yellow  color  of  the  sericin  layer. 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.        223 

lowish  opalescent  white;  the  same  color  is  nearly  always  to  be 
found  over  the  entire  breadth;  (b)  narrow  side,  exactly  similar 
to  the  preceding. 

2.  Yama-mai  silk:    (a)  broad  side,  generally  of  a  pure  bluish 
opalescent   white;    also   darker   bluish   to   almost   black   tones; 
nearly  all  of  the  colors  are  brilliant;    (b)  narrow  side,  shows  all 
colors,  very  brilliant  and  contrasted;    darker  and  blackish  tones 
also  occur. 

3.  Tussah  silk  (from  Bombyx  selene):    (a)  broad  side,  shows 
all   colors,  very  brilliant;    thickness  of  the  fibre  very  uneven, 
hence  the  colors  change  through  the  length;   the  thick  parts  are 
dark  blue  and  reddish  violet,  while  the  thinner  parts  are  yellow 
or  orange;    (b)  narrow  side,  shows  bright  red  and  bright  green 
colors,  though  often  but  slightly  visible;    the  colors  form  long 
flecks;  often  only  dark  gray  to  black. 

4.  Tussah   silk    (from   Bombyx   mylitta):     (a)  broad   side,    a 
bluish  opalescent  white  prevailing;    also  brown,  gray,  and  black 
tones;    the  colors  occur  in  flecks  like  preceding,  though  scarcely 
ever  dark  blue,  but  mostly  bright  orange  to  red  or  brown;    (b) 
narrow  side,  color  a  dull  gray  with  bright  red  or  green  flecks;  the 
general  appearance  is  very  similar  to  the  preceding  silk. 

5.  Ailanthus  silk:    (a)  broad   side,   bright  yellow  or  yellow- 
brown  to  gray-brown  colors;    (b)  narrow  side,  nearly  all  colors, 
but  rather  soft  and  not  very  contrasted,  seldom  very  bright,  but 
rather  dull;  short  flecks  of  green,  yellow,  violet,  red,  or  blue. 

6.  Senegal  silk:    (a)  broad  side,  bright  yellowish  white,  gray 
to  brown,  seldom  bluish  white  in  color;    (b)  narrow  side,  faint 
and  dull  gray,  brown,  to  blackish  colors,  seldom  bright  colors. 

10.  The  following  micro-analytical  tables  are  given  by  Hoh- 
nel  for  the  qualitative  determination  of  vegetable  fibres: 

I.   TABLE   FOR  THOSE   VEGETABLE   FIBRES   BOTANICALLY 
DESIGNATED   AS   HAIR   STRUCTURES. 

i.  (a)  Each  single  fibre  consists  of  a  single  cell (see  4). 

(b)  Each  fibre  consists  of  two  cells,  namely,  a  short,  thick, 
underlying  cell,  and  an  overlying  pointed,  principal  cell.     The 


224  THE   TEXTILE  FIBRES. 

fibres  are  grayish  brown,  scarcely  0.5  cm.  long;  hard,  woolly, 
lifeless,  thin-walled,  but  round- stapled.  Such  fibres  form  the 
thick  upper  coating  on  the  leaves  of  the  Cycada  macrozamia  of 
New  South  Wales,  and  are  used  as  vegetable  wool  in  upholster}-. 

(c)  Each  single  fibre  consists  of  a  series  of  cells,  hence  is  a 
cellular  fibre.     The  cells  are  golden  yellow  to  brown  in  color, 
generally  clinging  together,  and  empty.     The  fibre  as  a  whole  is 
highly  lustrous,  but  very  harsh  and  brittle;  very  thin- walled,  flat, 
and  ribbon- shaped;    frequently  twisted  on  its  axis;    broad,  and 
0.5  to  2  cms.  long.     Such  fibres  form  the  thick  coating  on  the 
leaves  of  various  ferns  (Cibotium)  in  Asia,  Australia,  and  Chili. 
The  material  is  used  for  upholstery  under  the  name  of  pulu. 

(d)  Each  fibre  consists  of  numerous  cells  growing  side  by  side, 
or  of  several  series  of  such;  forms  the  so-called  tuft (see  2). 

2.  (a)  Hairs  straight,  stiff;  white  to  dirty  yellow  in  color.  .  (see  3). 

(b)  Hairs  woolly,  tough,  brownish  violet  in  color,  4  to  6  mm. 
long;    consisting  of  long  cotton-like,   flat,    twisted,   spiral  cells, 
the  walls  of  which  are  frequently  thick  and  undulating;   the  con- 
tents of  the  cells  moderately  abundant,  yellow  to  violet,  and  in 
part  colored  red  with  hydrochloric  acid.     This  fibre  covers  the 
small,  egg-shaped,  flattened  fruit  of  the  new  Holland  composite 
Cryptostemma  calendulaceum.     It  is  used  in  Australia  as  a  stuffing 
material. 

(c)  Hairs  woolly,  harsh,  reddish  yellow  in  color;    the  cells  are 
very  thin- walled,  colorless,  and  generally  empty;   in  places,  how- 
ever, filled  with  a  homogeneous  reddish- yellow  substance;  where 
two  cells  come  together  side  by  side  there  are  to  be  noticed  round 
spots.     The  individual  cells  are  relatively  broad,  extremely  varied, 
and  irregularly  thick;    irregularly  bent  in  places  and  frequently 
knitted  together.     This  fibre  forms  the  coating  of  a  plant  (Hibis- 
cus?} growing  in  Cuba;  as  employed  for  upholstery  materials  it 
goes  by  the  name  of  Ma]agua. 

3.  (a)  The  hairs  are  i  to  3  cm.  long,  and  on  the  average  are  under 
50  //.  wide;  they  consist  of  two  layers  of  cells  which  grow  into  one 
another.     The  inner  walls  are  rough;    the  outer  walls  are  thin 
and  indented,  hence  lie  close  against  the  inner  portion;   the  sec- 
tion walls  are  quite  noticeable  and  thick;    the  tufts  end  in  2  to 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         225 

6  pointed,  often  hook- shapecT cells;  the  end  cells  show  numerous 
pores;  weakly  lignified.  This  fibre  consists  of  the  ripe  fruit 
spicula  of  cotton-grass,  Eriophorum  angustijolium,  E.  latijolium, 
etc Cotton-grass  (see  Fig.  53). 


FIG.  53. — Fibres  of  Cotton-grass  or  Vegetable  Silk 
The  sharp  fractures  show  the  brittle  nature  of  the  fibres. 

(b)  The  fibres  are  5  mm.  long;  mean  breadth  of  the  tufts 
8  to  1 6  //,  the  widest  being  under  30  //;  the  tufts  do  not  end  with 
sharp-pointed  cells;  the  section- walls  under  low  magnification 
appear  as  little  knots  and  are  usually  quite  noticeable.  This 
fibre  is  obtained  from  the  small,  lance-like  fruit  of  the  reed 
mace,  Typlia  angustijolia,  which  grows  on  a  small  shaft,  and 
carries  the  hairs  on  the  other  end.  It  is  used  for  upholstery  and 
other  filling  material Reed-mace  hair  (see  Fig.  54). 

4.  (a)  The  fibres  are  flat,  woolly,  frequently  twisted  in  a  spiral 
manner  on  their  axes;   not  lignified (see  5). 

(b)  The  fibre  is  generally  cylindrical,  stiff,  not  twisted;  some- 
what lignified,  hence  colored  red  with  indophenol  or  phloro- 
glucol (see  6). 

5.  (a)  Fibres   i  to   5  cm.  long;    white   to   yellowish   brown;    12 
to  42  {j.  thick Cotton  (see  Fig.  55). 

(b)  Fibres  only  9.5  cm.  long;  very  thin;  usually  consisting  of 
tufts;  violet-brown  in  color.  See  above  under  2  (b). 

Cryptostemma  hairs. 

6.  (a)  The  product  consists  of  grassy  spicula  with  a  hairy  cover- 
ing; the  hairs  are  5  to  8  mm.  long  and  about  10  to   15  //  wide; 


226 


THE    TEXTILE  FIBRES. 


the  thickness  of  the  wall  of  the  thick,  cylindrical- pointed  hairs 
remains  rather  uniform  up  to  the  point  it- 
self, hence  the  latter  appears  very  thick; 
spots  are  often  observed.  This  fibre  is 
upholstery  material  from  Saccharum  offici- 
nale Sugar-cane  hairs. 

(b)  The  product  consists  of  short  white 
fibres,  about  8  to   24  /«  in  width,  and  of 
oval,  flat   fruit- shells,  4  mm.    wide    and    5 
mm.  long;   the  hairs  are  broadened  at  the 
base,  hence  generally  knife- shaped;     thick- 
walled,  with  transverse,  fissure-like  marks; 
the  upper  portion  of  the  hair  is  very  thin 
and  rough- walled;  colorless;    the  ends  are 
usually  blunt  and  contain  a  granular  matter; 
slightly  lignified,  especially  at  the  base. 

Poplar  cotton. 

(c)  The  product  consists  entirely  of  hairs 
and  is  almost   entirely  free  from  accidental 

impurities Vegetable  dmvn  and  silk. 

7.  (a)  The  fibres  have  two  to  five  longitudi- 
nal ridges  on  the  walls,   which   are   either 
crescent- shaped  or   quite  flat,  running  into 

FIG   54.— Reed-mace  network  at  the  base'>   tnese  ridges  are  broad 
Hair.    (Hohnel.)        and  difficult  to  discern  in  a  surface  view  of 

B,  ripe  fruit  at/;    h,  hair  ,,       -,  .  A. 

around  fruit;  A,  por-  the  nbre>  yet  sometimes  very  apparent;    the 
tion  of  hair;   z,  cells;  maximum  thickness  about  ^   «;   white  or 

k,  knotted  structure. 

yellowish  in  color.  These  fibres  are  the  seed- 
hairs  of  Apocyneen  and  Asclepiadeen. .  Vegetable  silk  (see  Fig.  56). 
(b)  The  fibres  are  without  ridges;  transverse  ridges  frequently 
at  the  base  or  as  a  network.  Maximum  thickness  generally 
under  35  p.\  yellowish  to  brown.  These  fibres  consist  of  the 
hairs  which  cover  the  fruit-pods  of  Bombaca. 

Vegetable  down  (Fig.  59;  see  13). 

8.  (a)  The  hairs  are  3.5  to  4.5  cm.  long,  and  the  largest  are  50  to 
60  fi  in  diameter.  •. (see  9). 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         227 

(b)  The  fibres  are  1.5  to  4  cm.  long,  and  the  largest  are  35  to 

45  fj.  in  diameter (see  10). 

9.  (a)  The  fibres  are  narrowed  at  the  base,  and  directly  above 
are  strongly  swollen,  and  up  to   100  ,«  in  thickness;    numerous 


FIG.  55.— Cotton  Fibres.     (Hohnel.) 

a,  portion  swollen  with  Schweitzer's  reagent;  cf,  shreds  of  cuticle;  cr,  rings  of 
cuticle;  ce,  cellulose;  i,  dried  protoplasmic  canal;  b.  various  cotton  fibres 
with  sections  above;  /,  lumen;  d,  twists;  s,  granulations  on  cuticle. 

pores  at  the  base;   the  fibres  grow  brush-like  on  a  stem,  are  yel- 
lowish and  harsh.     This  is  vegetable  silk  from  Senegal. 

Strophantus  (see  Fig.  56). 


228 


THE    TEXTILE  FIBRES. 


(b)  The  fibres  are  white,  firm,  and  tough,  not  harsh;   form  a 
hairy  tuft  or  crown.     This  is  vegetable  silk  from  India. 

Beaumontia  grandi flora  (see  Fig.  57), 

(c)  Yellow  rod  fibres,  weak,  stiff,  straight,  and  harsh. 

Calotropis  procera,  Senegal. 


FIG.  56.— Fibre  of  Strophantus. 
a,  longitudinal  view;  b,  cross-sections. 

10.  (a)  At  the  base  of  the  hair  there  are  spots  or  pores  ....  (see  n)- 
(b)  Spots  or  pores  lacking.    Vegetable   silk  from  Asclepias 

cornutii,  curassavica,  etc (see  Fig.  58). 

11.  (a)  Spots  large;  round  or  oblique;   the  walls  of  the  fibre  are 
not  thicker  at  the  base  than  at  the  upper  portion;   the  ridges  on 
the  fibre  are  remarkably  well  developed,  the  hairs  are  strongly 
bent  back  at  the  base.    Vegetable  silk  from  Calotropis  gigantea. 

(b)  Spots  small,  no  longitudinal  markings;  walls  thicker  than 
the  foregoing  fibre;  ridges  less  noticeable  and  often  apparently 
lacking (see  12). 

12.  (a)  Hairs  narrowed  at  the  base Hoya  viridi  flora. 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.        229 

(b)  Hairs  not  narrowed  at  all,  or  scarcely  so Marsdenia. 

13.  (a)  The  hairs  have  mesh-like  ridges  at  the  base,   situated 
obliquely,  or  have  spiral  ridges (see  14). 


m 


FIG.  57. — Vegetable  Silk  from  Beaumontia  grandi flora.     (Hohnel.) 

b,  base  of  fibre;    s,  pointed  ends;    q,  cross-section;    m,  middle  portion  of   fibre; 

•w,  cell -wall;  /,  longitudinal  ridges. 

(b)  Without  mesh-like  ridges  at  the  base (see  15). 

14.  (a)  Base  broader,  thin-walled,  with  oblique,  mesh-like  ridges 
or  spiral  swellings,  which  often  extend  to  a  considerable  dis- 
tance. Points  very  thin-walled,  gradually  tapering,  not  ended 
sharply  ;  frequently  containing  a  reddish-brown  homogeneous 


230 


THE    TEXTILE  FIBRES. 


FIG.  58. — Vegetable  Silk  from  Asclepias  cornutii. 
a,  longitudinal  view;   b,  cross-sections;   r,  thickened  ridges;  w,  cell-wall. 


FIG.  59. — Ceiba  Cotton. 

a,  longitudinal  views;   r,  base  of  fibre,  showing  network  at  n;   p,  pointed  end; 
b,  cross-section,  showing  cell-walls. 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         231 


granular  substance;  fibre  not  very  stiff,  usually  notched.    Base  con- 
tains no  marrow.     Vegetable  down  jrom 
Eriodendron  anjractuosum. 

(b)  Quite  similar,  but  the  ends  are 
not  so  tapering;  without  marrow;  whole 
fibre    somewhat    rough- walled.       Vege- 
table    down      jrom      Bombax      hepta- 
phyllum. 

(c)  Very   similar   to   (a),  but   walls 
of  fibre  are  quite  roughened,  and  con- 
tain at  intervals  throughout   its  length 
a  granular  marrow;   base  thick- walled, 
mesh  -  like  fibrous   ridges,   but  neither 
spirally  developed  nor  very  broad — at 
most  only  one- sixth  of  the  width  of  the 
fibre;     ends,    as    before,    thick- walled. 
Vegetable     down,    Ceiba    cotton,    jrom 

Bombax  ceiba (see  Fig.  59). 

15.  (a)  Raw  fibre,  brown,  rough- walled; 
walls    i   to  7    jj.  thick;    not    indented; 
points  without  marrow;    stiff  and  very 
sharp  at  end;  base  not  broadened,  often 

contains    granular    matter.      Vegetable  FlG    ^_ochroma    iagopus 
down  jrom  Ochroma  Iagopus. 

(see  Fig.  60). 

(b)  Raw  fibre,  yellowish,  thin- walled, 
walls  very  uneven  in  thickness;  fre- 
quently weakly  developed  longitudinal  ridges;  just  at  the  base 
the  wall  is  very  thick.  Vegetable  down  from  Cochlospernum 
gossypium. 


v •- 


(Hohnel.) 

,    middle    part   of  fibre; 
base;      s,   pointed   end; 
lumen;       q,      cross-section; 
iu,  cell-\ 


232  THE   TEXTILE  FIBRES. 

II.    GENERAL  TABLE   FOR  THE   DETERMINATION   OF   THE 
VEGETABLE   FIBRES. 

Including  cotton,  as  well  as  the  more  important  fibres  derived 

from  bast  or  sclerenchymous  tissues. 

» 

A.  Fibres  Colored  Blue,  Violet,  or  Greenish  with  lodin  and 
Sulphuric  Acid. 

(a)  BAST  FIBRES  AND  COTTON.  (Cotton,  flax,  hemp,  sunn 
hemp,  ramie,  Roa  fibre.) 

I.  The  cross- sections  become  blue  or  violet  with  iodin  and 
sulphuric  acid;  show  no  yellowish  median  layer;  the  lumen  is 
often  filled  with  a  yellowish  marrow. 

1.  Cross-sections:  they  occur  either  singly  or  in  small  groups; 
the  single  sections  do  not  join  over  one  another;    are  polygonal, 
and  have  sharp  edges;    iodin    and    sulphuric  acid  colors  them 
blue  or  violet;    they  show  closely  packed,  delicate  layers;    the 
lumen  appears  as  a  yellow  point. 

Longitudinal  appearance:  with  iodin  and  sulphuric  acid, 
quite  blue;  it  appears  transparent,  quite  uniformly  thick;  smooth 
or  delicately  marked;  joints  frequent;  indications  of  dark  lines 
running  through,  which  are  usually  crossed;  enlargements  on  the 
fibre,  especially  at  the  joints,  frequent;  the  lumen  apears  as  a 
narrow  yellow  line;  the  natural  ends  of  the  fibres  are  sharply 
pointed;  length  4  to  66  mm.,  thickness  15  to  37  /*. 

Linen  or  Flax  (see  Fig.  68). 

2.  Cross-sections  single  or  very  few  in  a  group,  loosely  held 
together;    polygonal  or  irregular,  mostly  flat,  very  large;    colored 
blue  or  violet  with  iodin  and  sulphuric  acid;    stratification   not 
noticeable;    the  lumen  is  large  and  irregular;    frequently  filled 
with  a  dark  yellow  marrow;  radial  fissures  frequently  apparent. 

Longitudinal  appearance:  many  of  the  fibres  remarkably 
broad;  the  width  of  a  single  fibre  very  uneven ;  smooth  or  striped ; 
very  often  ruptures  in  the  wall;  with  iodin  and  sulphuric  acid, 
blue  or  violet;  the  lumen  readily  seen;  very  broad,  often  contain- 
ing a  dark  yellow  marrow;  joints  noticeable;  dark,  transverse 
lines  frequent,  often  crossing  each  other;  the  ends  are  relatively 


QUALITATIVE  ANALYSIS  OF  THE    TEXTILE  FIBRES.         233 

thick- walled  and  blunt;    length  60  to  250  mm.,  thickness  up  to 

8o// China  grass,  Ramie  (see  Fig.  42). 

3.  Cross-sections:  not  many  in  the  groups;  polygonal;  mostly 
with  straight  or  slightly  curved  sides  and  blunt  angles;  the 
lumen  is  contracted  lengthwise  regularly;  frequently  contains 
a  yellow  marrow,  many  sections  are  surrounded  by  a  thin,  green- 
ish-colored layer;  not  closely  joined  to  one  another.  The  sec- 
tions often  show  very  beautiful  radial  marks  or  fissures  and  con- 
centric layers;  the  various  layers  are  colored  differently. 

Longitudinal  appearance,  as  with  China  grass;  proportional 
dimensions  similar Roa  fibre  (see  Fig.  61). 


FIG.  61. — Section  of  Roa  Fibre. 
/,  fissures  in  inner  wall. 

4.  Cross-sections  always  isolated,  rounded,  various  shapes, 
mostly  kidney- shaped;  with  iodin  and  sulphuric  acid,  blue  or 
violet;  lumen  contracted,  line- shaped,  often  containing  a  yel- 
lowish marrow;  no  stratification. 

Longitudinal  appearance:  fibres  always  separate;  with 
iodine  and  sulphuric  acid,  a  fine  blue;  streaked  and  twisted; 
lumen  broad,  distinct,  frequently  contains  yellowish  marrow; 
ends  blunt;  the  entire  fibre  not  soluble  in  concentrated  sulphuric 
acid;  coated  with  a  very  thin  cuticle;  length  10  to  60  mm,, 
breadth  12  to  42  // Cotton  (see  Fig.  55). 

II.  Cross-section  blue  or  violet  with  iodin  and  sulphuric 
acid;  polyhedral,  rounded  or  irregular;  always  surrounded  by  a 
yellow  median  layer. 

i.  Cross-sections  always  in  groups,  with  angles  more  or  less 
rounded  off,  lying  very  close  to  one  another;  all  of  them  sur- 


234  THE   TEXTILE  FIBRES. 

rounded  by  a  thin,  yellowish  median  layer;  the  lumen  is  line- 
shaped,  single  or  forked,  often  broad,  with  inturning  edges,  with- 
out marrow;  good  concentric  stratification;  the  different  strata 
being  differently  colored. 

Longitudinal  appearance:  with  iodin  and  sulphuric  acid, 
blue,  greenish,  or  dirty  yellow;  fibres  irregular  in  thickness,  fre- 
quently with  appended  portions  of  yellowish  median  layer;  joints 
and  transverse  lines  frequent;  stripes  very  distinct;  the  lumen  is 
not  very  apparent,  but  broader  than  linen;  ends  are  broad,  thick- 
walled,  and  blunt,  often  branched;  length  5  to  55  mm.,  breadth 
16  to  50  p. Hemp  (see  Fig.  62). 

2.  Cross-sections  in  large  groups,  lying  very  close  together  and 
touching;  very  similar  to  those  of  hemp;  often  crescent- shaped. 
Polygonal  or  oval,  with  lumen  of  varying  size,  frequently  contain- 
ing yellowish  marrow;  lumen  usually  not  line- shaped,  but  irregu- 
lar; a  broad  yellow  median  layer  always  present,  from  which  the 
blue  inner  strata  are  easily  distinguished;  stratification  very  dis- 
tinct, as  with  hemp. 

Longitudinal  appearance:  as  with  hemp,  except  in  dimen- 
sions, which  are:  length  4  to  12  mm.,  breadth. 25  to  50  /*. 

Sunn  hemp  (see  Fig.  47). 

(b)  LEAF  FIBRES.  (With  vascular  tissue;  without  jointed 
structure.  Esparto  and  Pineapple  fibre.) 

1.  Cross-sections    in    large,    compact,    often    crescent-shaped 
groups;   very  small;   pale  blue  or  violet  with  iodin  and  sulphuric 
acid;   surrounded  by  a  thick,  shell- like  network  of  median  layer; 
rounded  or  polygonal;    lumen  like  a  point  or  streak;    thick  cut- 
tings  appear   greenish   or   even   yellow;    frequently   bundles   of 
vascular  tissue  with  one  or  two  rows  of  thick,  yellow-colored  fibres. 

Longitudinal  appearance:  Fibres  slender,  regular,  very 
thick- walled,  smooth;  lumen  often  invisible,  generally  as  a  fine 
line;  ends  are  tapered  with  needle-like  points;  color  with  iodin 
and  sulphuric  acid,  blue,  often  but  slightly  pronounced;  fre- 
quently present  short,  thick,  stiff,  completely  lignified  fibres 
from  vascular  tissue;  length  5  mm.,  breadth  6  //. 

Pineapple  fibre. 

2.  Cross-sections  in    groups;    with  iodin  and  sulphuric  acid, 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.        235 


FIG.  62.— Hemp.     (Hohnel.) 
c,  epidermis  of  hemp;  6,  ends  of  fibres;  c,  cross-section;  d,  longitudinal  view. 


236  THE   TEXTILE  FIBRES. 

mostly  blue,  though  also  yellow;  often  with  pronounced  stratifi- 
cation; 'the  outer  strata  frequently  yellow,  while  the  inner  are 
blue;  rounded  or  oval,  seldom  straight- sided;  lumen  like  a  point. 
Longitudinal  appearance:  the  fibres  are  short;  blue  with 
iodin  and  sulphuric  acid;  thin,  very  firm,  smooth,  uniform  in 
breadth;  lumen  yellow,  line-shaped;  ends  are  seldom  pointed, 
mostly  blunt  or  chiselled  off,  or  forked;  length  1.5  mm.,  breadth 
12  jj. Esparto  (see  Fig.  63). 


FIG.  63.— Esparto-grass.     (Hohnel.) 
t,  short  schlerenchymous  elements;  /,  cells;  /,  fibres;  h,  hairs;  e,  epidermal  cells. 

B.  Fibres  which  are  Colored  Yellow  with  Iodin  and  Sulphuric 
Acid. 

(a)  DICOTYLEDONOUS  FIBRES.  (Without  vascular  bundles; 
lumen  showing  remarkable  contractions.  Including  Jute,  Abel- 


QUALITATIVE  ANALYSIS  OF   THE    TEXTILE  FIBRES.         237 

moschus,   Gambo  hemp,  Urena,   and  Manila  hemp;    the  latter 
sometimes  shows  vascular  tissue.) 

I.  Cross- sections    in    groups;    polygonal    and    straight- lined, 
with  sharp  angles;    lumen  round  or  oval,  smooth,  and  without 
marrow;    cross- sections  with   narrow  median  layers  showing  the 
same  color  as  the   inner  strata  with  iodin   and  sulphuric  acid; 
lengthwise  appearance  shows  the  lumen  with  contractions. 

1.  Cross-sections  polygonal,  straight- lined;  lumen,  in  general, 
large,  round,  or  oval. 

Longitudinal  appearance:  fibres  smooth,  without  joints  or 
stripes;  lumen  distinctly  visible;  broad;  with  contractions;  the 
ends  always  blunt  and  moderately  thick;  ends  have  wide  lumen; 
length  1.5  to  5  mm.,  breadth  20  to  25  ft Jute  (see  Fig.  40). 

2.  Cross-sections  in  general  somewhat  smaller  than  jute;   sides 
straight,   with  sharp  angles;    lumen  frequently  like  a  point  or 
line,  oval,  occasionally  pointed;   not  so  large  as  with  jute. 

Longitudinal  appearance:  fibres  quite  even  in  thickness, 
smooth,  with  occasional  joints  or  stripes;  lumen  narrow,  irregu- 
lar in  thickness,  contractions  frequent;  the  ends  are  broad, 
blunt,  frequently  thickened;  length  i  to  1.6  mm.,  breadth  8  to 
20  p. Pseudo-jute  or  Musk  mallow  of  Abelmoschus. 

II.  Cross- sections  in  groups,  lying  close  together;    polygonal, 
with  sharp  lines  and  sharp  or  rounded  angles;    lumen  without 
marrow;    the    median    layer  is  broad,  and  with  iodin  and  sul- 
phuric acid  is  colored  perceptibly  darker  than  the  inner  layer  of 
cell- wall;  the  lumen  in  places  is  completely  lacking. 

1 .  Cross-sections  more  or  less  polygonal,  with  sharp  or  slightly 
rounded  angles;   the  lumen  is  small,  becoming  broader  and  more 
oval  as  the  section  is  more  rounded;    the  median  layer  is  broad, 
and  is  colored  considerably  darker  than  the  cell- wall  with  iodin 
and  sulphuric  acid;  stratification  occasional  and  indistinct. 

Longitudinal  appearance:  the  fibres  vary  much  in  thick- 
ness; lumen  generally  narrow,  with  decided  contractions,  and  in 
some  parts  totally  absent;  the  broader  fibres  often  striped;  ends 
are  blunt  and  generally  thickened;  length  2  to  6  mm.,  breadth 
14  to  33  ft Gambo  hemp  (see  Fig.  48). 

2.  Cross-sections    always   in   groups;    small,    polygonal,    with 


238 


THE   TEXTILE  FIBRES. 


sharp  angles;   lumen  very  small,  appearing  as  a  point  or  a  short 
line. 

Longitudinal  appearance:  occasionally  jointed  or  striped; 
lumen  with  decided  contractions,  in  some  places  altogether  lack- 
ing; ends  blunt  and  sometimes  thickened;  length  i.i  to  3.2 
mm.,  breadth  9  to  24  ;/. 

Pseudo-jute  from  Urena  sinuata  (see  Fig.  64). 


FIG.  64.— Pseudo-jute.     (Hohnel.) 

I,  longitudinal  view;   v,  interruption  of  lumen;    e,  end  with  thick  wall;   q,  cross- 
section;  m,  median  layer;  L,  small  lumen. 


(b)  MONOCOTYLEDONOUS  FIBRES.  (Occurring  as  vascular 
bundles  together  with  bast;  the  lumen  exhibits  no  contractions; 
in  Manila  hemp  vascular  bundles  often  lacking.  Includes  New 
Zealand  flax,  Manila  hemp,  Sansevieria  or  bowstring  hemp,  Pita 
hemp,  and  Yucca  fibre.) 

I.  Cross-sections  generally  rounded,  occasionally  polygonal; 
the  lumen  is  always  rounded,  without  contractions  longitudinally; 
median  layer  indistinct,  or  only  as  a  narrow  line;  vascular  tissue 
small  in  amount,  or  altogether  lacking. 

i.  Cross-sections  small,  generally  rounded,  lying  loosely  sepa- 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         239 

rated;  very  rounded  angles;  lumen  small,  round  or  oval,  without 
marrow. 

Longitudinal  appearance:  the  fibres  are  stiff  and  thin; 
the  lumen  is  small  but  very  distinct,  and  uniform  in  width;  the 
ends  are  pointed;  no  markings  and  no  joints;  length  5  to  15  mm., 

breadth  10  to  20  // New  Zealand  -flax  (see  Fig.  49). 

2.  Cross-sections  polygonal,  with  rounded  angles,  in  loosely 
adherent  groups;  lumen  large  and  round,  often  containing  yellow 
marrow. 

Longitudinal  appearance:  fibres  uniform  in  diameter; 
walls  thinner  than  those  of  New  Zealand  flax;  lumen  large  and 
distinct;  ends  pointed  or  slightly  rounded;  silicious  stegmata 
adhering  to  the  fibre-bundles  and  to  be  found  in  the  ash  as  bead- 
like  strings,  insoluble  in  hydrochloric  acid;  length  3  to  12  mm., 

diameter  16  to  32  /* Manila  hemp  (see  Fig.  50). 

II.  Cross- sections  polygonal;  lumen  large  and  polygonal, 
with  angles  quite  sharp ;  median  layer  lacking  or  only  in  the  form 
of  a  thin  line. 

1.  Cross-sections  distinctly  polygonal,  often  with  blunt  angles, 
lying  compactly  together;   lumen  large  and  polygonal,  with  sharp 
angles;  no  stratification  in  cell- wall. 

Longitudinal  appearance:  fibres  thin  and  smooth;  lumen 
large  and  distinct;  ends  pointed;  length  1.5  to  6  mm.,  diameter 
15  to  26  ft Sansevieria  fibre. 

2.  Cross-sections  polygonal,  not  many  sections  to  a  group,  but 
lying  compactly  together;    angles  slightly  rounded;    lumen  not 
very  large,   polygonal,   often  having  blunt   angles;    besides  the 
bast  fibre  sections  are  to  be  noticed  some  vascular  bundles  in  the 
form  of  large  spirals. 

Longitudinal  appearance:  fibres  uniform  in  diameter; 
lumen  not  very  large,  but  uniform;  no  structure;  ends  pointed 
and  sometimes  blunt;  length  1.3  to  3.7  mm.,  diameter  15  to  24  //. 

Aloe  hemp  (see  Fig.  51). 

3.  Cross-sections  polygonal,  with  straight  lines;   angles  sharp, 
though  sometimes  blunt;    sections  lie  compactly  together;    lumen 
large  and  polygonal,  though  angles  not  so  sharp. 

Longitudinal  appearance:   fibres  stiff,  and  often  very  wide 


240  THE   TEXTILE  FIBRES. 

towards  the  middle;  lumen  large;  ends  broad,  thickened,  and 
often  forked;  large,  shining  crystals  to  be  found  in  the  ash,  which 
are  derived  from  the  chisel-shaped  crystals  of  calcium  oxalate 
clinging  to  the  outside  of  the  fibre;  these  crystals  are  often  £  mm. 
in  length;  length  of  fibre  i  to  4  mm.,  diameter  20  to  32  //. 

Pita  hemp  (see  Fig.  65). 


FIG.  65. — Pita  Hemp  (Agave  americana) . 
A,  longitudinal  section;    B,  cross-section;   e,  blunt  ends. 

III.  Cross- sections  polygonal  and  small,  sides  straight,  with 
very  sharp  angles ;  lumen  small,  usually  as  a  point  or  line-shaped ; 
sections  lie  compactly  together  and  are  surrounded  by  a  thick, 
distinct  median  layer. 

i.  Cross-sections  as  above. 

Longitudinal  appearance:  fibres  very  narrow;  lumen  also 
very  narrow;  longitudinal  ridges  frequent;  ends  usually  sharp- 
pointed;  length  0.5  to  6  mm.,  diameter  10  to  29  /<. 

Yucca  fibre  (see  Fig.  66). 


QUALITATIVE  ANALYSIS  OF   THE    TEXTILE  FIBRES.         241 

C.  Analytical  Review  of  the  Chief  Vegetable  Fibres. 

i.  Those  occurring  as  thick,  fibrous  bundles,  also  with  vascu- 
lar tissue  (monocotyledonous  fibres) (See  2). 

Vascular  tissue  absent;  sections  and  fibres  always  single; 
round  or  kidney-shaped  by  being  pressed  together;  fibres  with  a 
thin  external  cuticle  insoluble  in  concentrated  sulphuric  acid,  and 
not  swelling  (vegetable  hairs) (see  7). 


FIG.  66. — Yucca  Fibre. 
A,  longitudinal  view;    B,  cross-section;    m,  median  layer;    /,  transverse  markings. 

Vascular  tissue  absent;  the  fibres  are  bundles  of  bast  fila- 
ments; sections  occurring  two  or  more  together  (mostly  true 
dicotyledonous  fibres) (see  13). 

2.  Lumen  very  narrow,  line- shaped,  much  thinner  than  the 
wall (see  3). 

Lumen  in  thickest  fibres  almost  as  wide,  or  even  wider, 
than  the  wall;  completely  lignified (see  4). 

3.  Sections  polygonal,  sides  straight,  with  sharp  angles;    com- 
pletely lignified;  diameter  10  to  20  /*. . .  Yucca  fibre  (see  Fig.  66). 

Sections  rounded  to  polygonal;  often  flattened  or  egg- 
shaped  ;  the  inner  strata  at  least  not  lignified ;  diameter  4  to  8  ,«. 

Pineapple  fibre. 

4.  Thick,  strongly  silicified  stegmata  occurring  at  intervals  on 
the  fibre- bundles  in  short  to  long  rows,  sometimes  but  few;   these 
are  four-cornered,  have  serrated  edges,  and  show  a  round,  bright, 
transparent  place  in  the  middle;    they  are  easily  seen  after  the 
fibre  has  been  macerated  with  chromic  acid,  and  are  about  30  // 
in  length;   in  the  ash  of  fibres  previously  treated  with  nitric  acid, 


242  THE   TEXTILE  FIBRES. 

they  appear  in  the  form  of  pearly  strings,  often  quite  long,  and 
insoluble  in  hydrochloric  acid;  they  are  joined  together  length- 
wise; the  fibres  are  thick- walled,  with  fissure-like  pores;  3  to 
12  mm.  long;  the  fibre-bundles  are  yellowish  and  lustrous. 

Manila  hemp  (see  Fig.  48). 

Stegmata  present,  sometimes  in  small,  sometimes  in  large 
quantities;  they  are  lens-shaped,  small  (about  15  /<  wide),  and  are 
fastened  to  the  exterior  fibres  of  the  bundles  by  serrated  edges; 
in  the  ash  of  the  fibre  they  melt  together  in  the  form  of  indistinct 
globules;  in  the  ash  of  fibres  previously  boiled  in  nitric  acid  they 
appear  as  yeast-cells,  joined  together  in  round  skeletons  of  silica; 
the  fibres  are  often  thin- walled,  with  numerous  pores;  i  to  2  mm. 
in  length ;  the  raw  fibres  generally  brown  and  rough Coir. 

Stegmata  absent,  hence  the  fibres  are  not  accompanied  by 
silicified  elements (see  5) . 

5.  Fibre-bundles  covered  externally  at  intervals  with  crystals 
of  calcium  oxalate,  at  times  up  to  0.5  mm.  in  length;  lustrous, 
with  quadrangular  sections,  chisel-shaped  at  the  ends,  hence  they 
appear  as  thick,  needle-shaped  crystals;    when  present  in  large 
numbers  these  crystals  occur  in  long  rows  which  are  frequently 
visible  to  the  naked  eye,  and  always  easily  recognizable  under  the 
microscope,  especially  in  the  ash.     The  fibre-bundles  are  mostly 
thick,  and  their  outer  fibres  (as  a  result  of  their  preparation)  fre- 
quently contain  fissures  or  are  torn;    thickness  of  the  walls  very 
uneven;   fibres  often  much  widened  at  the  middle. 

Pita  hemp  (see  Fig.  65). 

Without  crystals,  generally  thin;  in  cross-section  usually 
less  than  100  fibres  to  a  bundle;  thickness  of  walls  and  lumen 
very  uniform (see  6). 

6.  Sections  mostly  round,  not  very  compact;    lumen  usually 
thinner  than  the  wall,  but  never  a  single  line;   in  section  round  or 
oval;  vascular  tissue  in  but  small  amount. 

New  Zealand  -flax  (see  Fig.  49). 

Sections,  on  one  side  at  least,  polygonal;  section  of  lumen 
polygonal,  with  angles  more  or  less  sharp;  generally  as  wide  or 
wider  than  the  wall;  vascular  tissue  frequent. 

Aloe  hemp  (see  Fig.  51). 


QUALITATIVE  ANALYSIS  OF  THE  TEXTILE  FIBRES.         243 

7.  Fibres   mostly   rope- shaped,    twisted,    externally   streaked, 
generally  possessing  fine  granules  or  marked  with  little  lines, 
therefore   rough;     thin  to  thick  walls;     cross-sections   squeezed 
together,  or  round  to  kidney- shaped,  hence  the  fibre  has  more  or 
less  the   shape  of  a  flat  band;   section  of   lumen  more  or  less 
arched,  line- shaped,  frequently  containing  yellow  marrow;    con- 
sists of  pure  cellulose  with  the  exception  of  the  thin  cuticle. 

Cotton  (see  Fig.  55). 

Fibres  not  twisted,  smooth  externally,  and  without  longi- 
tudinal markings;  fibres  not  flat,  sections  round;  walls  generally 
very  thin;  sometimes,  however,  they  are  thick;  lignified,  scarcely 
swelling  in  ammoniacal  copper  oxide.  . .  .  Vegetable  down  | 

Vegetable  silks  )  ( 

8.  Fibres  on  the  inside  possess  from  2  to  5  broad  ridges,  which 
at  times  are  very  noticeable,  at  others  scarcely  visible;    they  run 
lengthwise  in  the  fibre,  and  in  section  are  semicircular;    on  this 
account   the   walls   appear   unequal   in   thickness   when   viewed 
longitudinally;   the  maximum  thickness  is  about  35  //. 

Vegetable  silks  (see  9). 

Fibres  without  ridges;  maximum  thickness  mostly  30  to 
35  jj. Vegetable  down  (see  12). 

9.  Largest  diameters  50  to  60  /*;  length  3.5  to  4.5  cm. .  (see  10). 
Largest  diameters  35  to  45  /£;  length  1.5  to  4  cm. .  (see  n). 

10.  Fibres  contracted  at  the  lower  end,  and  directly  above 
abruptly  swelling,  becoming  80  //  thick ;   the  under  portion  of  the 
swollen  area  contains  numerous   pore-canals;    fibres  feather- like 
or  brush-like,  arising  from  a  straight  shaft. 

Vegetable  silk  from  Senegal. 

Contrary  to  the  above  the  fibres  originate  from  one  point, 
like  a  fan;  remarkably  strong,  curved  backwards;  very  firm. 

Vegetable  silk  from  India. 

Like  the  foregoing,  but  the  fibre  is  stiff,  straight,  weak, 
and  brittle Calotropis  procera. 

11.  Thickened  ridges  very  noticeable;    in  the  cross- sections 
often  occurring  in  the  form  of  a  semicircle;   bound  together  in  a 
strictly  reticulated  manner. 

Vegetable  silk  from  Aschpias  cornutii. 


244  THE   TEXTILE  FIBRES. 

Thickened  ridges  indistinct,  projecting  but  slightly  in 
the  cross- section Vegetable  silk  from  Asdepias  curassavica. 

12.  Raw  fibre,  yellowish;    broadened  at  the  lower. end  (up  to 
50  //);  also  reticular  thickening  or  transverse  markings;  wall  i  to 
2  fi  thick Bombax  cotton  (Fig.  59) 

Raw  fibre,  brown;  the  lower  end  contracted  and  not  show- 
ing reticulated  thickenings;  fibre  almost  altogether  thin- walled, 
though  just  at  the  lower  end  very  thick-walled. 

Cochlospernurn  gossypium. 

13.  Thick  fibre-bundles,  whose  outer  surface  contains  at  inter- 
vals series  of  thick  silicious  plates,  having  sharp  indented  edges 
and  a  round,  hollow  space Manila  hemp  (see  under  4). 

Silicious  plates  absent ;  lengthwise  the  lumen  often  exhibits 
remarkable  contractions,  while  the  wall  is  very  uneven  in  thick- 
ness; at  intervals,  indeed,  the  lumen  is  almost  entirely  inter 
rupted;  joints  and  transverse  fissures  along  the  fibre;  transverse 
markings  and  lines,  which  appear  somewhat  like  zones  or  knots, 
are  completely  lacking,  or  are  very  rare  and  indistinct;  com- 
pletely lignified,  hence  colored  yellow  with  iodin  and  sulphuric 
acid (see  14). 

Silicious  plates  absent,  also  remarkable  contractions  of 
the  lumen;  thickness  of  the  walls  very  uniform ;  joints  and  fissures 
along  the  fibre,  transverse  lines  and  markings  frequent,  hence 
the  fibre  often  appears  as  if  it  contains  swollen  knots;  unligni- 
fied,  or  only  lignified  on  the  external  layer  of  membrane,  hence 
lengthwise  the  fibre  is  colored  blue  with  iodin  and  sulphuric  acid 
or  violet  or  green,  or  at  the  most  colored  yellow  in  places .  .  (see  17). 

14.  Exterior  layers  of  membrane   narrow   and   showing   the 
same  coloration  with  iodin  and  sulphuric  acid  as  the  inner  layers, 
hence  the  same  as  the  entire  cross-section;    the  lumen   hardly 
ever  completely  interrupted (see  15). 

Median  layer  in  sections  wide;  colored  considerably 
darker  with  iodin  and  sulphuric  acid;  lumen  often  completely 
interrupted (see  16). 

15.  Lumen  in  gem- nil  lar^e,  diameter  as  wide  or  only  a  little 
narrower  than  the  wall;    in  section  round  or  oval,  seldom  as  a 
point;  no  crystals  of  calcium  oxalate True  jute  (see  Fig.  40). 


QUALITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.         245 

Lumen  usually  small,  diameter  much  narrower  than  the 
thick  wall  in  section  frequently  as  a  point;  crystals  of  calcium 
oxalate  of  frequent  occurrence  (detected  by  ignition). 

Pseudo-jute  (Abelmoschus)  (see  Fig.  67). 


FIG.  67. — Abelmoschus  Jute.     (Hohnel.) 

I,  longitudinal  view;   q,  cross-section;   e,  ends;   L,  small  lumen;   v,  narrowing  of 

lumen. 

1 6.  Lumen  almost  always  considerably  smaller  than  the  wall; 
ends  usually  very  thick- walled  and  narrow:  calcium  oxalate  crys- 
tals of  frequent  occurrence. 

Pseudo-jute  (Urena  sinuata)  (see  Fig.  64). 

Lumen  frequently  as  wide  as  or  wider  than  the  wall,  mostly 

narrower  however;  ends  broad  and  blunt .  Gambo  hemp  (see  Fig.  48). 

17.  The  lumen  in  the  middle  portion  of  the  fibre  generally 
line-shaped,   much  narrower  than  the  wall;    ends  never  blunt, 
always  sharply  pointed;    sections  isolated  or  in  small  groups, 
regular  in  diameter,  sharp-angled  and  straight-sided  polygonals; 


246  THE   TEXTILE  FIBRES. 

without  separate  median  layer;  iodin  and  sulphuric  acid  colors 
the  entire  section  blue  or  violet;  the  lumen  in  the  cross-section  is 
very  small,  or  as  a  point,  containing  a  marrow  which  is  colored 
yellow  with  iodin  and  sulphuric  acid.  .Linen  or  Flax  (see  Fig.  68). 


FIG.  68.— Linen  Fibre. 
Showing  jointed  structure  or  knot-like  formation  at  /. 

Lumen,  at  least  in  the  central  portion  of  the  fibre,  always 
much  thicker  than  the  walls;  in  section  generally  more  or  less 
flattened,  narrow  to  broad,  egg-shaped  or  oval.  Fibre  ends 
blunt,  never  sharply  pointed;  sections  almost  never  sharp-angled 
polygonals,  but  more  or  less  oval  or  elliptical,  and  with  a  rounded 
boundary (see  18). 

18.  Breadth  of  fibre  up  to  80  //;  maximum  length  15  to  60  mm. ; 
sections  always  in  compact  groups,  which  often  consist  of  many 
fibres,  with  thinner  or  thicker  layers  of  membrane  which  are  col- 
ored yellow  with   iedjn  and  sulphuric  acid,  hence  the  fibre  is 
never  colored  a  pure  blue,  but  dirty  blue  to  greenish,  and  in  places 
yellow;  ends  often  have  side  branches  projecting (see  19). 

19.  Lignified  exterior  membranes  very  thin;    lumen    in    sec- 
tion narrow,  very  seldom  broad,  fissure-like  or  line-shaped,  often 
branched,  without  marrow Hemp  (see  Fig.  62). 

Lignified  exterior  layers  often  as  wide  as  the  interior  layers, 
or  wider;  the  interior  layers  are  often  loosened  in  places  from  the 
exterior  ones  where  they  are  thin;  lumen  in  section  scarcely  ever 
napjpw  or  fissure- shaped,  but  broad,  oval,  or  long;  often  contain- 
ing a  yellowish  marrow Sunn  hemp  (see  Fig.  47). 


CHAPTER  XVII. 
QUANTITATIVE  ANALYSIS  OF  THE  TEXTILE  FIBRES. 

i.  Wool  and  Cotton  Fabrics. — The  finishing  materials  and 
coloring- matters  should  be  removed  as  far  as  possible  by  boiling 
the  sample  to  be  examined  first  in  a  i  per  cent,  solution  of  hydro- 
chloric acid,  then  in  a  dilute  solution  of  sodium  carbonate  (about  a 
one- twentieth  per  cent,  solution),  and  finally  in  water.  A  por- 
tion of  the  material  is  then  dried  at  100°  C.  for  an  hour  for  until 
constant  weight  is  obtained)  and  weighed;  this  weight  will  repre- 
sent the  actual  amount  of  true  fibre  present  in  the  sample,  and 
the  loss  will  correspond  to  moisture.  Then  steep  for  twelve  hours 
in  a  20  per  cent,  solution  of  sulphuric  acid,  and  mix  with  three 
volumes  of  alcohol  and  water;  filter  off  the  dissolved  cotton  and 
wash  the  residue  of  wool  well  with  alcohol.  Dry  at  100°  C.,  and 
weigh;  this  will  give  the  amount  of  wool  present.  The  following 
example  will  illustrate  this  method: 

Grams. 

Sample  weighed 3-62 

After  treatment  with  acid  and  alkali 3-  X7 

Finishing  materials,  etc o .  45 

0 

After  drying  at  100°  C 2.77 

Loss  as  water * o .  40 

Wool  left  after  treating  with  acid i .  96 

Cotton,  by  difference 0.81 

Hence  the  composition  of  this  sample  would  be  as  follows: 

Per  Cent. 

Finishing  materials 12 . 43 

Moisture 1 1 . 05 

Wool 54- 14 

Cotton 22.38 


247 


248  THE    TEXTILE  FIBRES. 

Another,  and  perhaps  a  better,  method  for  determining  the 
relative  amounts  of  wool  and  cotton  in  a  mixed  fabric  or  yarn, 
especially  when  the  cotton  is  present  in  rather  large  proportion, 
is  to  remove  the  wool  by  treatment  with  a  dilute  boiling  solution 
of  caustic  potash.  The  estimation  is  carried  out  in  the  following 
manner: 

The  sample  to  be  tested  is  treated  with  hydrochloric  acid  and 
sodium  carbonate  solutions  as  before,  in  order  to  remove  finish- 
ing materials,  and  after  thorough  washing  is  dried  at  100°  C.  and 
weighed.  This  gives  the  weight  of  the  dry  fibres.  The  weighed 
sample  is  then  boiled  for  twenty  minutes  in  a  5  per  cent,  solution 
of  caustic  potash.*  The  residue  is  well  washed  in  fresh  water, 
and  redried  at  100°  C.  and  weighed.  The  residue  consists  of 
cotton,  the  wool  having  been  dissolved  by  the  caustic  potash. f 
If  the  residue  becomes  disintegrated  and  cannot  be  washed  and 
dried  as  one  piece,  it  should  be  collected  on  a  tared  filter  (one 
which  has  been  dried  at  100°  C.  and  weighed)  and  well  washed 
with  water,  then  dried  at  100°  C.  and  weighed.  The  tared  weight 
of  the  filter  subtracted  from  the  latter  will  give  the  weight  of  the 
cotton  particles. 

Examples : 

(a)  Analysis  of  a  cloth  sample: 

Grams. 

Weight  of  sample 5-42 

After  treatment  with  acid  and  alkali 5-io 

Finishing  materials,  etc o.  32 

After  drying  at  100°  C 4. 26 

Loss  as  water o .  84 

Cotton  left  after  boiling  with  caustic  alkali 2.82 

Wool,  by  difference i .  44 

*  It  is  not  advisable  to  use  caustic  soda  instead  of  caustic  potash,  as  the  results 
obtained  are  not  as  satisfactory. 

t  In  case  yarns  are  to  be  analyzed,  the  preliminary  treatment  should  consist 
of  a  thorough  scouring  with  soap.  After  drying  in  the  air,  the  loss  in  weight  should 
be  recorded  as  grease  and  miscellaneous  dirt.  On  then  drying  at  100°  C.  to  con- 
stant weight,  the  loss  will  represent  moisture,  and  the  residue  dry  fibre.  This 
is  then  analyzed  as  in  the  manner  above  described. 


QUANTITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.       249 
Hence  the  composition  of  this  sample  would  be : 

Per  Cent. 
Finishing  materials 5 . 98 

Moisture 15 . 50 

Cotton 52 . 03 

Wool 26 . 49 


Since  the  cotton  itself  suffers  a  slight  loss  on  boiling  with 
caustic  potash,  it  is  customary,  as  a  correction,  to  add  to  the  cotton 
found  5  per  cent,  of  its  weight,  and  to  subtract  a  corresponding 
amount  from  that  of  the  wool.-  On  applying  this  correction  the 
result  of  the  above  analysis  would  become: 

Per  Cent. 
Finishing  materials 5 . 98 

Moisture 15 . 50 

Cotton 54-63 

Wool 23.89 


Figured  on  the  weight  of  the  dry  fibre,  the  relative  amounts  of 
the  two  fibres  in  the  above  samples  would  be : 

Per  Cent. 
Cotton 69 .  5 

Wool 30.5 

100. OO 

Since,  however,  in  making  mixes,  the  dry  weights  of  the  fibres 
are  not  taken,  we  may  assume  the  weight  to  include  the  normal 
amount  of  moisture  held  by  each  fibre.  As  the  normal  amount 
of  moisture  for  cotton  is  about  8  per  cent.,  and  for  wool  about 
1 6  per  cent.,  we  may  approximate  very  closely  to  the  true  compo- 
sition of  this  sample  by  adding  to  the  dry  weights  of  the  fibres  their 
respective  amounts  of  moisture;  the  relative  amounts  of  cotton 
and  wool  then  become: 

Grams. 
Weight  of  cotton  found 2 . 82 

Add  5  per  cent,  correction 0.14 

2.96 

This  represents  92  per  cent,  of  air-dry  cotton. 

Hence  air-dry  cotton  would  be 3. 22 

Weight  of  wool  found i .  44 

Subtract  correction  for  cotton o.  14 

1.30 


or 


250  THE   TEXTILE  FIBRES. 

This  represents  84  per  cent,  of  air-dry  wool. 

He»ce  air-dry  wool  would  be i .  54 

Therefore  the  relative  amounts  of  cotton  and  wool  on  this 
basis  would  be: 

Per  Cent. 
Cotton 65  .8 

Wool 34.2 

(b)  Analysis  of  a  yarn : 

Grams. 
Weight  of  sample 5  . 65 

Scoured  in  soap,  washed,  and  air-dried 4-97 

Grease,  etc o .  68 

Dried  at  100°  C 4 . 32 

Loss  as  moisture o .  65 

Weight  of  filter-paper  dried  at  100°  C 1.16 

•     Weight  of  filter  and  residue  of  cotton  dried  at 

100°  C 3.66 

Weight  of  dry  cotton 2 . 50 

Add  5  per  cent,  correction 2 . 62 

Correct  for  moisture  at  8  per  cent 2 .85 

Weight  of  dry  wool  by  difference  (with  correction),  i .  70 
Correct  for  moisture  at  16  per  cent 2 .02 

Hence  the  composition  of  this  yarn  may  be  expressed  as: 

Per  Cent. 
Grease,  etc 1 2 .  oo 

Moisture 1 1 . 50 

Cotton 44 . 25 

Wool 32.25 

IOO.OO 

And  the  relative  proportion  of  the  two  fibres  would  be  as 
follows : 

Dry  at  1 00°  C.  Air-dry. 

Cotton 60 . 7  58 . 5 

Wool 39.3  41.5 


When  a  rough,  approximate  analysis  of  a  wool-cotton  is 
desired,  it  will  be  sufficient  only  to  weigh  the  sample,  boil  for 
fifteen  minutes  in  a  5  per  cent,  solution  of  caustic  potash,  wash 
well  in  acidulated  water,  then  in  fresh  water,  and  dry  in  the  air. 
On  reweighing,  the  amount  of  cotton  will  be  ascertained,  while 


QUANTITATIVE  ANALYSIS  OF   THE   TEXTILE  FIBRES.       251 

the  loss  in  weight  will  represent  the  amount  of  wool.  Results 
attained  by  this  process  are  usually  sufficiently  accurate  to  give 
one  a  practical  idea  of  the  approximate  relative  amounts  of  wool 
and  cotton  present  in  a  sample  of  mixed  goods. 

Another  method  for  the  separation  of  wool  from  cotton  in 
their  quantitative  estimation  is  treatment  of  the  mixed  fibres 
with  an  ammoniacal  solution  of  copper  oxide,  whereby  the  cotton 
is  dissolved;  and  after  washing  and  drying,  the  residue  of  wool  is 
weighed.  This  method,  however,  is  not  very  satisfactory,  as  it 
is  difficult,  in  the  first  place,  to  obtain  a  complete  and  thorough 
solution  of  the  cotton;  and  in  the  second  place,  the  wool  will  be 
considerably  affected  by  this  treatment  and  more  or  less  decom- 
posed. Consequently  the  results  obtained  by  this  method  are 
not  very  accurate,  and  it  cannot  be  recommended. 

2.  Wool   and   Silk.— Silk  is   soluble  in  boiling  hydrochloric 
acid,  whereas  wool  is  not  soluble  in  this  reagent  to  any  extent. 
Hence  this  method  may  be  utilized  for  the  quantitative  estima- 
tion of  the  two  fibres  when  occurring  together.     The  sample  is 
first  treated  with  acid  and  alkali  in  the  manner  already  described 
in  order  to  remove  foreign  materials  other  than  actual  fibre.     It 
is  then  dried  and  weighed;    then  boiled  in  concentrated  hydro- 
chloric acid  for  fifteen  minutes.     The  residue  is  collected,  washed 
thoroughly,  dried  again,  and  weighed.     The  loss  in  weight  repre- 
sents silk,  while  the  weight  of  the  residue  represents  wool.    An- 
other method,  and   one  which  is  perhaps  more  satisfactory,  is 
to  dissolve  the  silk  by  treatment  with  an  ammoniacal  solution  of 
nickel   oxide,  in  which   reagent  the  silk  is  very  readily  soluble 
even  in  the  cold.     It  only  requires  a  treatment  of  about  two  min- 
utes to  completely  dissolve  the  silk  in  most  silk  fabrics  other  than 
plush.     Richardson*  found  that  by  this  treatment  cotton  lost 
only  0.45  per  cent,  in  weight  and  wool  only  0.33  per  cent.     As 
silk  in  plush  goods  and  similar  fabrics  is  much  more  difficult  to 
dissolve,  it  is  recommended  to  boil  such  material  with  the  nickel 
solution  for  ten  minutes  under  a  reflux  condenser.     By  this  treat- 
ment cotton  will  lose  only  0.8  per  cent,  in  weight.     The  nickel 
solution  is  best  prepared  by  dissolving  25  grams  of  crystallized 

*  Jour.  Soc.  Chem.  Ind.,  xii.  430. 


252  THE   TEXTILE  FIBRES. 

nickel  sulphate  in  80  c.c.  of  water;  add  36  c.c.  of  a  20  per  cent, 
solution  of  caustic  soda,  carefully  neutralizing  any  excess  of  alkali 
with  dilute  sulphuric  acid.  The  precipitate  of  nickel  hydroxide 
is  then  dissolved  in  125  c.c.  of  strong  ammonia,  and  the  solution 
diluted  to  250,  c.c.  with  water.  Instead  of  the  above  reagent,  a 
boiling  solution  of  basic  zinc  chloride  may  be  employed  for  the 
purpose  of  dissolving  the  silk.  This  latter  solution  is  obtained  by 
heating  together  1000  parts  of  zinc  chloride,  850  parts  of  water,  and 
40  parts  of  zinc  oxide  until  complete  solution  is  effected.  Rich- 
ardson recommends  that  the  sample  to  be  examined  should  be 
plunged  two  or  three  times  into  the  boiling  solution  of  zinc  chloride, 
care  being  taken  that  the  total  time  of  immersion  does  not  exceed 
one  minute.  The  zinc  chloride  solution  should  be  sufficiently 
basic  and  concentrated  in  order  to  obtain  good  results.  Under 
the  best  conditions,  cotton  loses  about  6.5  per  cent,  in  weight,  and 
wool  from  1.5  to  2.0  per  cent. 

3.  Silk  and  Cotton. — The  methods  given  above  for  separating 
silk  from  wool  may  also  be  used  for  the  separation  and  quantita- 
tive determination  of  silk  in  fabrics  containing  this  fibre  in  con- 
junction with  cotton. 

Another  method  for  separating  silk  from  cotton  is  by  the  use 
of  an  alkaline  solution  of  copper  and  glycerin,  which  serves  as  an 
excellent  solvent  for  the  silk.  The  reagent  is  prepared  as  follows: 
Dissolve  16  grams  of  copper  sulphate  in  150  c.c.  of  water,  with 
the  addition  of  10  grams  of  glycerin;  then  gradually  add  a  solution 
of  caustic  soda  until  the  precipitate  of  copper  hydrate  which  is 
at  first  formed  just  redissolves.  This  solution  readily  dissolves 
silk,  but  is  said  not  to  affect  either  wool  or  the  vegetable  fibres. 
Richardson,  however,  has  found  that  cotton  heated  with  this 
solution  for  twenty  minutes  (the  time  necessary  to  dissolve  silk  in 
plush)  lost  from  i  to  1.5  per  cent,  in  weight  and  became  friable 
and  dusty  on  drying;  while  woolen  fabrics  lost  from  9  to  16  per 
cent,  in  weight.  Hence  the  reagent  would  be  useless  in  the  analy- 
sis of  fabrics  containing  wool. 

4.  Wool,   Cotton,   and  Silk.— Samples  of  shoddy  frequently 
contain   all   three   of  these   fibres   present    in   greater  or   lesser 
amount,  and  often   it  is  desirable  to   know  at  least  the  approx- 


QUANTITATIVE  ANALYSIS   OF   THE   TEXTILE  FIBRES.       253 

imate  amounts  of  each  fibre  in  the  mixture.  A  method  of  pro- 
cedure recommended  is  the  following:  A  weighed  sample  of  the 
material  is  boiled  for  thirty  minutes  in  a  3  per  cent,  solution  of 
hydrochloric  acid,  washed,  and  then  boiled  for  thirty  minutes  in  a 
o.i  per  cent,  solution  of  soda-ash.  This  preliminary  operation  is 
similar  to  that  above  described  in  the  preceding  analyses,  and  is 
for  the  purpose  of  freeing  the  fibres  as  far  as  possible  from  extra- 
neous foreign  matter.  After  thorough  washing  and  air-drying, 
the  weight  of  the  sample  is  again  taken,  and  the  loss  will  represent 
miscellaneous  joreign  matter.  The  sample  is  then  dried  at  100°  C. 
to  constant  weight;  the  loss  in  weight  will  represent  moisture. 
The  sample  is  then  divided  into  two  weighed  portions;  the  first 
is  treated  for  five  minutes  with  a  boiling  solution  of  basic  zinc 
chloride  prepared  as  above  described,  washed  thoroughly  with 
acidulated  water,  then  with  fresh  water,  and  dried  at  100°  C. 
again.  The  loss  in  weight  will  represent  the  amount  of  silk 
present.  The  second  portion  of  the  sample  is  boiled  for  ten  min- 
utes in  a  5  per  cent,  solution  of  caustic  potash;  washed  thor- 
oughly, dried  at  100°  C.  and  weighed.  This  weight,  with  a  cor- 
rection of  5  per  cent,  added  to  it,  will  represent  the  amount  of 
cotton  present.  The  amount  of  wool  is  obtained  by  taking  the 
difference  between  the  total  weight  of  the  combined  fibres  and 
the  sum  of  the  weights  of  the  silk  and  cotton. 
Example: 

Grams. 
Sample  of  loose  shoddy  weighed 5 . 06 

Treated  with  acid  and  alkali,  and  air-dried 4-23 

Loss  as  foreign  matter o .  83 

Dried  at  100°  C 3 . 62 

Loss  as  moisture o .  61 

Divided  into  two  portions: 

Grams. 

(a)  weighed i .  95 

(6)   weighed i .  67 

(a)  treated  with  zinc  chloride i .  73 

Loss  as  silk 0.22 

(&)  .treated  with  caustic  potash,  residue  as  cotton 0.34 

Loss  as  wool i .  33 


254  THE    TEXTILE  FIBRES. 

Hence  the   composition   of   this  sample  on  the  basis  of  dry 
fibre  would  be: 

Per  Cent. 

Silk 11.3 

Cotton 21.5 

Wool 67.2 


Von  Remont  gives  the  following  method  for  analyzing  fabrics 
containing  a  mixture  of  silk,  wool,  and  cotton.  Four  quantities 
(A,  B,  C,  D)  of  2  grams  each  of  the  air-dried  material  are  weighed 
out.  Portion  A  is  kept  aside,  and  each  of  the  other  three  is 
boiled  for  fifteen  minutes  in  200  c.c.  of  water  containing  3  per 
cent,  of  hydrochloric  acid.  The  liquid  is  decanted,  and  the 
boiling  repeated  with  more  dilute  acid.  This  treatment  removes 
the  size  and  the  major  portion  of  the  coloring-matter.  Cotton  is 
nearly  always  decolorized  quite  rapidly,  wool  not  so  readily,  and 
silk  but  imperfectly,  especially  with  black-dyed  fabrics.  The 
samples  should  be  well  washed  and  squeezed  in  order  to  remove 
the  acid  liquor.  Portion  B  is  set  aside.  Portions  C  and  D  are 
then  placed  for  two  minutes  in  a  boiling  solution  of  basic  zinc 
chloride  (of  1.72  sp.  gr.,  and  prepared  as  above  described),  which 
dissolves  any  silk  present.  They  are  then  washed  with  water 
containing  i  per  cent,  of  hydrochloric  acid,  and  again  with  pure 
water,  until  the  washings  no  longer  show  the  presence  of  zinc. 
Portion  C  is  squeezed  and  set  aside.  Portion  D  is  boiled  gently 
for  fifteen  minutes  with  60-80  c.c.  of  caustic  soda  solution  (1.02 
sp.  gr.)  in  order  to  remove  any  wool.  The  sample  is  then  care- 
fully washed  with  water.  The  four  portions  are  next  dried  for 
an  hour  at  100°  C.,  and  then  left  exposed  to  the  air  for  ten  hours 
in  order  to  allow  them  to  absorb  the  normal  amount  of  hygro- 
scopic moisture.  The  four  samples  are  then  weighed,  and  call- 
ing a,  bj  c,  and  d  their  respective  weights,  we  shall  have 

a  —  b  =  dye  and  finishing  material ; 
6-c  =  silk; 
c  —  d  =  wool; 

d  =  cotton  (or  vegetable  fibre). 

This  method  is  open  to  objections,  as  the  plan  of  using  air- 


QUANTITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.       255 

dried  material,  then  drying  at  100°  C.,  and  subsequently  expos- 
ing to  the  air  again  before  reweighing,  is  liable  to  give  very  errone- 
ous results.  Richardson  recommends  that  the  samples  should 
be  thoroughly  dried  at  100°  C.  before  being  weighed  out,  and 
the  treated  portions  should  subsequently  be  dried  at  the  same 
temperature  before  weighing.  In  order  to  prevent  the  sample 
from  absorbing  moisture  during  weighing,  it  is  best  to  use  a  weigh- 
ing-bottle for  holding  the  dried  fibre.  The  sample  before  dry- 
ing is  placed  in  a  weighing-bottle  (the  weight  of  which  has  been 
ascertained  previously)  and  heated  in  an  air-oven  at  100°  C.  for 
the  time  specified,  during  which  the  coyer  of  the  weighing-bottle 
is  removed.  After  the  drying  process  is  completed  the  stopper 
is  replaced  in  the  weighing-bottle;  the  latter  is  taken  from  the 
oven,  allowed  to  cool,  and  is  then  weighed.  The  difference 
between  this  weight  and  the  weight  of  the  empty  bottle  will  give 
the  amount  of  dry  fibre. 

Treatment  with  a  boiling  solution  of  3  per  cent,  hydrochloric 
acid  for  the  purpose  of  removing  finishing  materials  is  rather  too 
severe,  as  the  acid  will  act  on  the  wool  and  the  cotton,  some- 
times causing  considerable  error.  Boiling  with  a  i  per  cent, 
solution  of  acid  for  ten  minutes  is  to  be  preferred. 

The  following  is  given  as  a  practical  method  to  determine  if 
shoddy  contains  cotton  and  silk  fibres :  Boil  10  grams  of  the  shoddy 
to  be  tested  for  one  hour  in  400  c.c.  of  water  containing  0.8  gram 
of  alum,  0.3  gram  of  tartar,  i  c.c.  of  hydrochloric  acid,  o.i  gram  of 
chrome,  and  0.05  gram  of  blue-stone.  Rinse  and  dye  with  0.3 
gram  of  logwood  extract.  Rinse  and  dry.  The  undyed  fibres  are 
then  picked  out  and  examined;  cotton  will  remain  white,  while 
silk  will  be  colored  a  dingy  red. 

The  analysis  of  heavy  pile  fabrics  containing  a  mixture  of 
fibres  is  especially  difficult  unless  the  fabric  is  disintegrated.  In 
the  analysis  of  plush  for  the  amount  of  silk  present,  Richardson 
suggests  treating  the  sample  with  a  boiling  solution  of  basic  zinc 
chloride  in  the  manner  previously  described;  but  when  silk  is  to 
be  determined  in  light  fabrics  (especially  in  the  presence  of  wool), 
it  is  best  to  treat  the  sample  for  one  to  three  minutes  with  a  cold 
solution  of  ammoniacal  nhkel  oxide.  He  gives  the  following 


256 


THE    TEXTILE  FIBRES. 


comparison  of  results  in  the  analysis  of  a  sample  of  plush,  using 
the  three  different  methods  for  dissolving  the  silk : 


By  Solution 
of  Ammoniacal 
Nickel  Oxide. 

By  Solution 
of  Basic 
Zinc  Chloride. 

By  Copper- 
glycerin 
Reagent. 

Moisture  and  finish  
Silk  
Cotton  

11-34 
45.60 
4.3.  60 

II  .OO 
45.00 
4.4  oo 

10.  04 
47.06 

i  ->    oo 

Samples  of  plush  with  hard  cotton  backs  may  best  be  analyzed 
by  successive  treatment  with  acid  and  copper-glycerin  reagent. 
On  other  cotton  material,  however,  this  method  is  not  suitable; 
nor  is  it  to  be  used  in  the  presence  of  wool,  as  this  fibre  is  consid- 
erably dissolved  by  the  copper-glycerin  reagent. 

The  following  table  by  Richardson  shows  a  comparison  of 
the  three  methods  employed  for  dissolving  silk : 


Fibre. 

Actually 
Present. 

Percentage  Obtained  by 

Ammoniacal 
Nickel  Oxide. 

Basic  Zinc 
Chloride. 

Copper-glvcerin 
Reagent. 

Silk 

5-84 
76.31 
I7-85 

5-92 
76.58 

I7-5° 

5-52 
80.08 
14.40 

18.80 
64.05 
I7-I5 

Wool        .          .... 

Cotton  

The  ammoniacal  nickel  oxide  solution  appears  to  give  the  best 
result;  hence  in  analyzing  a  sample  containing  silk,  wool,  and 
cotton,  it  is  best  to  first  remove  the  silk  by  means  of  this  reagent. 
The  insoluble  residue  left  after  this  treatment  is  boiled  with  a 
i  per  cent,  solution  of  hydrochloric  acid,  washed  well  in  fresh 
water,  and  then  boiled  for  five  to  ten  minutes  in  a  2  per  cent, 
solution  of  caustic  soda,  which  is  sufficient  to  completely  remove 
the  wool  without  materially  affecting  the  cotton. 

Allen*  also  recommends  the  ammoniacal  nickel  solution  for 
use  in  dissolving  silk  from  a  mixture  of  fibres.  His  method  of 
analyzing  a  textile  sample  is  as  follows:  The  yarn  or  fabric  is  cut 


*  Commer.  Org.  Anal.,  vol.  iv.  523. 


QUANTITATIVE  ANALYSIS   OF   THE    TEXTILE  FIBRES.       257 

up  very  fine  with  a  pair  of  scissors,  and  thoroughly  dried  at  100°  C. 
One  gram  of  the  material  thus  prepared  is  treated  with  40  c.c.  of 
the  cold  ammoniacal  nickel  oxide  solution  for  two  minutes.  The 
liquid  is  then  filtered,  and  the  residue,  consisting  of  wool  and 
cotton,  is  digested  for  two  or  three  minutes  in  a  boiling  solution 
of  i  per  cent,  hydrochloric  acid.  It  is  then  washed  free  from 
acid,  dried  at  100°  C.,  and  weighed.  To  separate  the  wool  from 
the  cotton  the  residue  is  boiled  with  about  50  c.c.  of  a  i  per  cent, 
solution  of  caustic  potash  for  ten  minutes,  and  the  solution  fil- 
tered. The  residue,  consisting  of  cotton,  is  washed  free  from 
alkali,  dried  at  100°  C.,  and  weighed. 

To  remove  gum  and  weighting  materials  from  goods  contain- 
ing silk,  Richardson  recommends  treatment  of  the  sample  with  a 
cold  2  per  cent,  solution  of  caustic  potash;  this  not  only  removes 
any  gum,  but  also  decomposes  any  Prussian  blue  that  may  be 
present  (as  a  bottom  under  the  black  dye),  so  that  the  iron  may 
be  more  easily  removed  by  subsequent  treatment  with  a  i  per  cent, 
solution  of  hydrochloric  acid.  Metallic  mordants,  however,  are 
difficult  to  remove  in  this  manner,  and  at  best  they  dissolve  only 
imperfectly;  it  is  best  to  calculate  their  amounts  from  the  quan- 
tity of  ash  left  after  the  ignition  of  the  sample. 

Oily  matter  (and  also  certain  dyes)  may  be  best  removed 
by  boiling  successively  with  methylated  spirits  and  ether.  By 
evaporation  of  the  solution  so  obtained  the  amount  of  oil  and  fat 
may  be  directly  determined. 

Hohnel  recommends  the  use  of  a  semi- saturated  solution  of 
chromic  acid  (see  p.  217)  for  the  quantitative  separation  of  mix- 
tures containing  wool,  cotton,  flax,  true  silk,  and  tussah  silk. 
On  boiling  such  a  mixture  of  fibres  in  this  solution  for  one  min- 
ute, the  wool  and  true  silk  will  be  completely  dissolved,  leaving 
as  a  residue  the  cotton,  flax,  and  tussah  silk. 

Other  methods  given  by  Hohnel  for  the  quantitative  analysis 
of  fabrics  containing  mixtures  of  the  fibres  mentioned  above  are 
as  follows: 

(a)  Any  true  silk  is  first  removed  by  boiling  for  half  a  minute 
in  concentrated  hydrochloric  acid;  tussah  silk  is  next  removed 
by  a  longer  boiling  in  the  acid  (three  minutes) ;  the  residue,  con- 


258  THE   TEXTILE  FIBRES. 

sisting  of  wool  and  vegetable  fibres,  is  further  separated  in  the 
usual  manner  by  boiling  in  caustic  potash  solution. 

(b)  The  fabric  is  first  boiled  in  caustic  potash  solution,  which 
dissolves  the  wool  and  the  true  silk,  and  leaves  as  a  residue  (4) 
tussah  silk  and  vegetable  fibre.    A  second  sample  is  boiled  for 
three  minutes  with  concentrated  hydrochloric  acid,   which  dis- 
solves both  varieties  of  silk  and  leaves  as  a  residue  (B)  wool  and 
vegetable  fibre.     Residue  A   is  then  boiled  three  minutes  with 
concentrated  hydrochloric  acid,  which   dissolves  the  tussah  silk 
and  leaves  the  cotton  as  a  final  residue.      By  subtracting  this 
amount  from  residue  B  the  amount  of  wool  is  obtained. 

(c)  A  sample  of  the  fabric  is  boiled  for  one  minute  in  a  semi- 
saturated  solution  of  chromic  acid,  which  dissolves  the  true  silk 
and  the  wool,  leaving  as  a  residue  the  tussah  silk  and  vegetable 
fibre.     From  this  residue  the  tussah  silk  is  removed  by  boiling 
for  three  minutes  in  concentrated  hydrochloric  acid,  leaving  the 
vegetable  fibre  as  a  final  residue.     A  second  sample  is  boiled  for 
three  minutes  in  concentrated  hydrochloric  acid,  which  dissolves 
the  silks  and  leaves  the  wool  and  vegetable  fibre  as  a  residue. 
From  this  the  amount  of  wool  can  be  obtained  either  by  boiling 
in  caustic  potash  solution,  or  by  subtracting  the  cotton  previ- 
ously estimated.     Finally,  the  amount  of  true  silk  may  be  found 
by  subtracting  the  sum  of  the  other  constituents  from  the  total  in 
the  original  sample. 

5.  Analysis  of  Weighting  in  Silk  Fabrics. — The  practice  of 
adding  to  the  weight  of  silk  in  the  dyeing  and  finishing  operations 
has  become  so  common  that  it  is  frequently  desirable  to  ascer- 
tain in  a  sample  of  silk  goods  the  amount  of  true  fibre  present 
and  the  amount  and  character  of  weighting.  Black-dyed  silk 
is  especially  liable  to  contain  a  very  large  amount  of  weighting 
materials;  sometimes  the  degree  of  weighting  may  reach  as  high 
as  400  per  cent.,  or  even  more.  Colored  silks  are  usually  not 
weighted  to  such  a  great  extent,  but  they  will  frequently  be  found 
to  also  contain  considerable  adulteration.  Black-dyed  silks  are 
mostly  loaded  with  Prussian  blue  and  iron  tannate,  the  latter 
being  obtained  by  immersing  the  silk  in  a  solution  of  pyrolignite 
or  nitrate  of  iron,  and  subsequently  in  a  solution  of  cutch  or  other 


QUANTITATIVE  ANALYSIS  OF   THE    TEXTILE  FIBRES.        259 

tannin.  Colored  silks  are  principally  weighted  with  tin  phos- 
phate obtained  by  treating  the  material  with  solutions  of  tin  per- 
chloride  and  sodium  phosphate.  Sometimes  light  colored  silks 
are  also  weighted  with  sugar,  magnesium  chloride,  etc.  Such 
materials  are  soluble  in  warm  water,  and  hence  their  use  is  easily 
detected. 

A  convenient  test  which  is  frequently  applicable  to  detect 
weighting  is  to  ignite  the  silk  fibre ;  if  it  is  heavily  weighted  it  will 
not  inflame,  but  gradually  smoulder  away  and  leave  a  coherent 
ash  retaining  the  original  form  of  the  fibre. 

In  general  the  substances  which  may  be  present  as  weighting 
materials  are  iron,  as  ferrocyanide  or  tannate;  tin,  as  tannate, 
tungstate,  phosphate,  silicate,  or  hydroxide;  chromium  com- 
pounds; the  sulphates  or  chlorides  of  sodium,  magnesium,  and 
barium;  organic  matters,  such  as  sugar,  glucose,  gelatin,  tannins, 
etc. 

The  following  method  for  the  qualitative  analysis  of  weight- 
ing materials  on  silk  has  been  recommended  by  Silbermann:* 
Substances  that  are  easily  soluble,  such  as  sugar,  glucose,  gly- 
cerin, magnesium  salts,  etc.,  are  estimated  directly  by  boiling 
the  silk  with  water,  and  testing  the  extract  with  Fehling's  solution, 
etc.f  From  2  to  3  grams  of  the  silk  are  ignited  and  the  ash  is 
tested  for  tin  (which  may  be  present  in  the  fibre  as  basic  chloride 

*  Chem.  Zeit.,  xvm.  744. 

f  Fehling's  reagent  is  an  alkaline  solution  of  copper  sulphate  containing  potassium 
tartrate.  It  is  prepared  in  the  following  manner:  34.639  grams  of  pure  crystallized 
copper  sulphate  are  dissolved  in  about  250  c.c.  of  water;  173  grams  of  Rochelle 
salt  (sodium  potassium  tartrate)  are  dissolved  in  the  same  quantity  of  water;  60 
grams  of  caustic  soda  are  similarly  dissolved.  The  three  solutions  are  then  mixed, 
and  the  mixture  diluted  to  1000  c.c.  with  water.  The  reagent  is  employed  as 
follows:  10  c.c.  of  the  solution  are  diluted  with  40  c.c.  of  water  and  brought  to 
a  boil;  there  is  then  added  a  portion  of  the  solution  to  be  tested  for  sugar  (or  glu- 
cose) which  has  previously  been  boiled  with  a  small  quantity  of  dilute  hydro- 
chloric acid.  If  sugar  is  present,  the  Fehling's  solution  will  be  decolorized  and 
a  bright  red  precipitate  of  cuprous  oxide  will  be  thrown  down.  This  test  may 
be  made  quantitative  by  using  a  known  quantity  of  sugar  solution,  filtering  off  the 
cuprous  oxide,  igniting,  and  finally  weighing  as  copper  oxide  (CuO).  In  order 
to  determine  the  amount  of  sugar  (or  glucose)  corresponding  to  this  latter,  refer- 
ence should  be  made  to  tables  constructed  by  Allihn  showing  the  proper  equiva- 
lents of  sugar  and  glucose  for  the  amounts  of  copper  oxide  determined. 


20o  THE   TEXTILE  FIBRES. 

and  stannic  acid),  chromium,  iron,  etc.*  Fatty  matters,  wax, 
and  paraffin  are  detected  by  extraction  with  ether  or  benzene,  f 
The  silk  is  soaked  in  warm  dilute  hydrochloric  acid  (1:2);  if 
the  fibre  is  almost  decolorized  by  this  treatment,  only  a  slight 
yellow  tint  remaining,  whilst  the  solution  assumes  a  deep  brown- 

*  These  metals  may  be  tested  for  in  the  ash  in  the  following  manner:  Moisten 
•with  a  few  drops  of  nitric  acid  and  re-ignite  in  order  to  be  certain  that  all  carbon 
is  removed.  Treat  the  residue  with  eight  to  ten  drops  of  strong  sulphuric  acid, 
and  gently  heat  until  fumes  are  evolved;  allow  to  cool  and  boil  with  water; 
dilute  to  about  100  c.c.  with  water,  and  then  pass  hydrogen  sulphide  gas 
through  the  liquid;  filter,  and  examine  the  solution  and  precipitate  as  follows: 
The  aqueous  solution  may  contain  zinc  or  iron;  add  a  few  drops  of  bromin- 
water  to  remove  excess  of  hydrogen  sulphide,  and  to  oxidize  any  iron  present 
to  the  ferric  condition;  boil,  then  add  ammonia  in  slight  excess;  boil  again, 
and  filter;  if  there  is  a  precipitate,  it  may  contain  iron;  if  so,  it  should  be 
brown  in  color;  dissolve  in  a  little  hydrochloric  acid  and  add  a  few  drops 
of  a  solution  of  potassium  ferrocyanide;  a  blue  color  will  confirm  the  presence 
of  iron.  The  filtrate,  which  may  contain  zinc,  should  be  heated  to  the  boil, 
and  a  few  drops  of  potassium  ferrocyanide  solution  added;  a  white  precipitate 
will  indicate  zinc.  The  original  precipitate  produced  by  the  treatment  with 
hydrogen  sulphide  is  next  examined.  This  may  contain  lead,  tin,  or  copper; 
it  is  fused  for  ten  minutes  in  a  porcelain  crucible  with  2  grams  of  a  mixture  of 
potash  and  soda  ash  together  with  i  gram  of  sulphur.  On  cooling,  the  mass 
is  boiled  with  water  and  filtered.  The  residue  may  contain  lead  and  copper; 
it  is  boiled  with  strong  hydrochloric  acid,  and  a  few  drops  of  bromin- water  are 
added  for  the  purpose  of  completely  oxidizing  any  copper  sulphide  present;  filter 
if  necessary,  and  add  to  the  filtrate  an  excess  of  ammonia,  when  a  blue  color  will 
indicate  presence  of  copper.  Acidulate  the  liquid  with  acetic  acid  and  divide 
into  two  portions:  to  the  first  add  a  few  drops  of  a  solution  of  potassium  bichro- 
mate; a  yellow  precipitate  will  confirm  the  presence  of  lead;  to  the  other  add 
a  few  drops  of  a  solution  of  potassium  ferrocyanide,  when  a  brown  precipitate 
or  coloration  will  indicate  presence  of  copper.  The  filtrate  from  the  residue  after 
the  above  fusion  is  acidulated  with  acetic  acid,  whe.n  a  yellow  precipitate  of  stannic 
sulphide  will  indicate  the  presence  of  tin.  The  latter  test  may  be  confirmed  by 
di^< living  the  precipitate  of  stannic  sulphide  in  hydrochloric  acid  and  bromin- 
water.  The  filtered  solution  is  then  boiled  with  small  pieces  of  metallic  iron  to 
reduce  the  tin;  the  liquid  is  diluted  and  filtered  and  a  drop  of  mercuric  chloride 
solution  is  added,  when  a  white  or  gray  turbidity  will  lx?  produced  if  tin  is  present. 

t  Japan  tram  silk  is  frequently  weighted  with  fatty  substances.  Tin-  normal 
amount  of  fat  in  raw  silk  never  exceeds  0.06  per  cent.  A  direct  determination 
of  the  fatty  matters  may  l>e  made  by  treating  5  grams  of  the  silk  sample  in  a  stop- 
pered flask  with  pure  lx-n/.cnc  three  or  four  times  su<  i  es.Mvely,  using  about  f>o 
c.c.  of  the  solvent  each  time  and  allowing  it  to  act  from  two  to  four  hours  with 
frequent  shaking.  The  several  portions  of  ben/ene  an-  brought  together  and 
evaporated  to  dryness  in  a  tared  dish  and  the  fatty  residue  is  weighed.  Another 
method  is  to  extract  with  ether  in  a  Soxhlet  apparatus. 


QUANTITATIVE  ANALYSIS  OF   THE   TEXTILE  FIBRES.       261 

ish  color  not  changed  to  violet  by  addition  of  lime-water,  it  is 
safe  to  conclude  that  the  silk  has  been  weighted  by  alternate 
passages  through  baths  of  iron  salts  and  tannin.  The  yellow 
color  of  the  fibre  is  due  to  a  residuum  of  tannin,  and  the  precise 
shade  (from  greenish  to  brownish  yellow)  enables  some  idea  to 
be  formed  as  to  the  nature  of  the  tanning  material  used  (sumac, 
divi-divi,  cutch,  etc.).  Decolorization  of  the  fibre,  the  acid 
extract  being  pink,  and  changing  to  violet  by  lime-water,  indi- 
cates a  logwood  black.  If  the  fibre  retain  a  deep  greenish  tint 
and  the  solution  be  yellow  and  unaffected  by  lime-water,  the 
black  is  dyed  on  a  bottom  of  Prussian  blue.  If  the  latter  has 
been  produced  during  the  final  stage  of  dyeing,  this  will  be  shown 
by  its  solubility  in  the  acid.  A  green  fibre  and  pink  solution, 
changing  to  violet  on  addition  of  lime-water,  indicate  a  logwood 
black  dyed  on  a  bottom  of  Berlin  blue.  In  the  hydrochloric 
acid  solution,  such  metals  as  lead,  tin,  iron,  chromium,  and  alu- 
minium may  be  determined.  Blacks  produced  by  artificial  dyes 
on  a  bottom  of  iron-tannin  or  iron-blue-tannin  may  be  recognized 
by  the  coloration  imparted  to  acid  and  caustic  soda  solutions. 
With  blacks  produced  solely  with  coal-tar  dyes,  treatment  with 
a  hydrochloric  acid  solution  of  stannous  chloride  does  not  affect 
anilin  and  alizarin  blacks;  naphthol  black  is  changed  to  reddish 
brown,  and  wool  black  becomes  yellowish  brown.  Tannin  mate- 
rials in  general  may  be  extracted  by  alkalies,  and  subsequently 
precipitated  and  distinguished  by  ferric  acetate.  To  remove  the 
whole  of  the  weighting  material  and  the  dye,  the  silk  should  be 
boiled  with  acid  potassium  oxalate,  washed  with  dilute  hydro- 
chloric acid,  and  finally  treated  with  soda  solution.  When  iron 
and  tin  are  both  present  in  the  fibre,  it  is  best  to  first  extract  the 
tin  by  treatment  with  a  solution  of  sodium  sulphide.* 

Vignon  has  proposed  using  the  specific  gravity  of  the  silk 
sample  as  a  means  of  determining  the  proportion  of  weighting 
materials  present;  but  this  method  cannot  be  recommended  as 

*  Persoz  recommends  in  testing  for  tin  weighting  on  dark  colored  and  black 
silks  to  boil  the  sample  for  a  few  minutes  in  concentrated  hydrochloric  acid.  Then 
dilute  and  filter  the  acid,  and  pass  hydrogen  sulphide  into  it,  when  a  yellow  pre- 
cipitate (SnS)  would  indicate  the  presence  of  tin. 


262  THE   TEXTILE  FIBRES. 

being  at  all  practical,  as  the  specific  gravity  of  the  weighting 
materials  themselves  would  have  to  be  known.  The  specific 
gravity  of  the  silk  may  readily  be  determined  as  follows:  A  small 
sample  is  weighed  as  usual  in  the  air;  it  is  then  suspended  in 
benzene  and  the  weight  again  taken.  The  difference  between 
the  two  weighings  will  give  the  loss  of  weight  in  benzene;  this 
lo£s  divided  into  the  original  weight  in  air  and  multiplied  by  the 
density  of  the  benzene  will  give  the  specific  gravity  of  the  silk. 
The  specific  gravity  of  silk  and  of  other  fibres  determined  in  this 
way  is  given  as  follows: 

Silk,  raw i .  30  to  i .  37 

Silk,  boiled-off 1.25 

Wool i .  28  to  i .  33 

Cotton i .  50  to  i .  55 

Mohair i .  30 

Hemp i .  48 

Ramie ^-S1  to  i  .52 

Linen i .  50 

Jute 1.48 

For  the  examination  of  white  silk  Allen  recommends  the 
following:*  (i)  The  total  soluble  weighting  materials  are  deter- 
mined by  treating  a  known  weight  of  the  sample  four  to  five  times 
with  hot  water,  redrying,  and  weighing.  As  the  hygroscopic 
character  of  silk  is  very  variable,  it  is  best  to  employ  a  blank 
sample  of  a  standard  silk,  and  after  redrying  until  the  blank 
sample  has  regained  its  normal  weight  the  test  sample  is  weighed, 
and  the  loss  represents  the  matters  soluble  in  water.  In  the 
solution,  after  suitable  evaporation,  glucose  may  be  determined 
directly  by  means  of  Fehling's  solution  (see  p.  259),  and  cane- 
sugar  after  inversion  by  boiling  with  dilute  hydrochloric  acid. 
Sulphates  and  chlorides  and  magnesium  f  may  be  detected  and 

*  Commer.  Org.  Anal.,  vol.  iv.  527. 

t  Sulphates  are  detected  by  taking  a  small  portion  of  the  solution  in  a  test- 
tube,  adding  a  few  drops  of  dilute  hydrochloric  acid  and  then  a  few  drops  of  a 
solution  of  barium  chloride;  the  production  of  a  white  precipitate  indicates  the 
presence  of  sulphates.  Chlorides  are  detected  by  adding  a  drop  of  nitric  acid 
to  ;i  test  portion  of  the  solution,  and  then  a  few  drops  of  a  solution  of  silver  ni- 
trate; a  white  precipitate  will  indicate  the  presence  of  chlorides.  Magnesium 
is  detected  by  adding  to  the  test  portion  of  the  solution  a  few  drops  of  ammonia 


QUANTITATIVE  ANALYSIS  OF  THE   TEXTILE  FIBRES.       263 

determined  as  usual.  Stannic  oxide  (if  the  silk  has  been  weighted 
with  tin  compounds)  will  be  left  as  a  white  residue  on  igniting  a 
sample  of  the  silk  in  a  porcelain  crucible.  If  much  tin  is  present, 
the  silk  will  burn  with  difficulty,  and  the  ash  will  retain  the  shape 
of  the  original  silk.  The  weight  of  the  ash  (assuming  it  to  be 
wholly  stannic  oxide,  SnO2)  may  be  calculated  to  the  form  in 
which  the  tin  exists  in  the  weighted  silk  (as  metastannic  acid, 
SnO2.H.,O)  by  multiplying  it  by  the  factor  1.12. 

Silbermann  *  recommends  for  the  analysis  of  white  silk  the 
further  procedure:  A  weighed  portion  of  the  silk  is  boiled  with 
dilute  hydrochloric  acid  to  dissolve  any  tannin  lakes  of  tin  or 
other  metals,  and  in  the  solution  tannin  is  tested  for  by  the  addi- 
tion of  an  excess  of  sodium  acetate  and  ferric  chloride.  If  tannin  . 
lakes  are  present,  the  determination  of  the  weighting  materials 
consists  in:  (i)  precipitation  of  the  tannin  from  the  aqueous 
solution  with  gelatin;  (2)  estimation  of  the  tannin  in  this  pre- 
cipitate, and  of  sugar,  etc.,  in  the  filtrate;  (3)  successive  treat- 
ment of  the  silk  with  dilute  hydrochloric  acid  and  sodium  car- 
bonate, and  precipitation  of  tannin  from  both  'solutions  by  means 
of  gelatin;  (4)  ignition  of  the  silk  and  determination  of  metallic 
weighting.  If  the  ash  is  not  completely  soluble  in  hot  moder- 
ately concentrated  hydrochloric  acid,  it  may  contain  barium 
sulphate  or  silica.  To  calculate  the  percentage  of  weighting 
material,  W,  in  the  silk  examined,  Silbermann  employs  the  fol- 
lowing formula,  in  which  a  is  the  weight  of  the  sample  before 
treatment,  b  the  weight  after  extraction  with  water,  p  the  stannic 
•oxide  left  on  ignition,  and  d  the  loss  in  weight  during  the  boiling 
of  the  fibre  itself.  This  is  taken  at  20  to  25  for  boiled-off  silk, 
5  to  9  for  souple  silk,  and  o.to  2  for  ecru. 


followed  by  a  solution  of  sodium  phosphate;  the  formation  of  a  white  precipi- 
tate indicates  the  presence  of  magnesium.  These  tests  may  be  made  quantita- 
tive by  taking  definite  aliquot  portions  of  the  solution,  collecting  the  precipitates 
produced,  and  after  ignition  in  a  porcelain  crucible  weighing  as  barium  sulphate, 
BaSO4,  silver  chloride,  AgCl,  and  magnesium  pyrophosphate,  MgjPjOy,  re- 
spectively. 

*  Chem.  Zeit.,  xx.  472. 


264  THE   TEXTILE  FIBRES. 

The  detection  of  tin  or  aluminium  compounds  in  the  weight- 
ing of  white  silk  may  be  carried  out  by  dyeing  a  sample  of  the 
silk  with  alizarin  in  the  presence  of  chalk,  then  rinsing  and  soap- 
ing. Unweighted  silk  will  retain  only  a  pink  color;  if  weighted 
with  tin,  the  color  will  be  orange,  and  if  weighted  with  aluminium, 
the  color  will  be  red. 

Dark  colored  and  black  silk  may  contain  hydroxides  of  tin, 
iron,  and  chromium,  fatty  matters,  tannin,  Prussian  blue,  and 
various  coloring-matters.  Treatment  of  logwood-dyed  silk  with 
hydrochloric  acid  (1.07  sp.  gr.)  at  50°  to  60°  C.  will  give  a  red 
color  in  the  absence  of  Prussian  blue,  or  leave  a  blue- black  color 
if  it  is  present.  If  Prussian  blue  is  suspected,  the  silk  should  be 
treated  with  dilute  caustic  soda,  the  solution  then  acidulated 
with  hydrochloric  acid,  and  a  few  drops  of  a  solution  of  ferric 
chloride  then  added ;  a  blue  precipitate  will  be  produced  if  Prussian 
blue  was  originally  present.  The  metallic  oxides  in  the  residue 
left  on  igniting  a  sample  of  the  silk  are  best  examined  by  fusing 
the  ash  with  a  mixture  of  nitre  and  sodium  carbonate  in  a  plati- 
num or  silver  crucible.  The  fusion  is  treated  with  water,  when 
the  tin  and  chromium  will  go  into  solution  as  sodium  stannate 
and  chromate  respectively,  and  the  iron  will  remain  insoluble  as 
ferric  oxide.  After  filtering  and  acidulating  the  filtrate  with 
hydrochloric  acid,  the  tin  may  be  thrown  down  as  sulphide  by 
treatment  with  hydrogen  sulphide,  and  after  filtering  off  the  latter 
the  chromium  is  precipitated  by  addition  of  ammonia.  For  the 
detection  of  tannin  a  sample  of  the  silk  should  be  boiled  in  water, 
and  a  few  drops  of  a  solution  of  ferric  acetate  added,  when  a 
blue-black  color  is  produced  in  the  presence  of  tannin.  The 
amount  of  tannin  may  be  determined  by  dissolving  it  from  the 
silk  by  means  of  an  alkaline  soap-bath,  and  finding  the  loss  of 
weight  on  redrying.  To  determine  the  total  proportion  of 
weighting  materials,  a  definite  quantity  of  the  silk  dried  at  110°  C. 
should  be  boiled  for  an  hour  in  a  2  per  cent,  solution  of  caustic 
soda,  and  then  in  dilute  hydrochloric  acid  (250  c.c.  of  commer- 
cial acid  per  litre).  This  treatment  is  repeated  four  times,  wash- 
ing the  sample  between  each  bath.  The  silk  must  be  carefully 
handled,  as  it  becomes  quite  brittle;  after  drying  at  110°  C.  it 


QUANTITATIVE  ANALYSIS   OF   THE   TEXTILE  FIBRES.       265 

is  weighed;  the  loss  in  weight  represents  the  total  weighting 
materials.  As  a  certain  loss  of  silk  occurs  in  this  treatment,  the 
amount  of  weighting  material  found  is  generally  somewhat  in 
excess  of  the  truth.  The  chief  source  of  error,  however,  is  in 
the  uncertainty  of  the  allowance  to  be  made  for  loss  in  the  weight 
of  the  silk  by  boiling  off.  For  boiled-off  silk  this  figure  (d)  is 
taken  at  25  per  cent.;  for  souple  silk  at  8  per  cent.;  for  ecru  at 
o  per  cent.;  and  for  fancy  silks  at  10  per  cent.  Calling  p  the 
original  weight  of  the  sample,  and  D  the  weight  after  treatment, 
the  percentage  of  weighting,  W,  may  be  calculated  from  the  fol- 
lowing formula: 

(loo-d)X(p-D) 
D 

In  cases  where  the  treated  silk  leaves  a  sensible  amount  (4)  of 
ash  on  ignition,  the  following  formula  must  be  used: 

(p 


D-i.2$A 

as  the  weight  of  the  ash,  if  multiplied  by  the  factor  1.25,  will  give 
approximately  the  amount  of  metallic  hydroxides  retained  by 
the  treated  silk. 

The  foregoing  method  of  Silbermann  is  not  sufficiently  accu- 
rate for  such  a  long  and  tedious  process. 

The  method  of  analyzing  weighted  silk  recommended  by 
Konigs  of  the  silk-conditioning  establishment  at  Crefeld  is  as 
follows:  (i)  Determine  moisture  by  drying  at  110°  C.  (2)  Fatty 
matters  by  extraction  with  ether.  (3)  Boil  out  the  silk-glue  with 
water.  (4)  Dissolve  out  Prussian  blue  with  dilute  caustic  soda; 
reprecipitate  by  acidifying  and  adding  ferric  chloride,  ignite  pre- 
cipitate with  nitric  acid,  and  weigh  as  ferric  oxide;  i  part  of 
Fe2O3  =  i.5  parts  of  Prussian  blue.  (5)  Estimate  stannic  oxide  in 
ash  of  silk  and  calculate  as  catechu-tannate  of  tin;  i  part  of 
SnO2=3.33  parts  of  catechu-tannate.  (6)  Estimate  total  ferric 
oxide  in  ash,  subtract  that  existing  as  Prussian  blue,  and  the 
amount  naturally  present  in  dyed  silk  (0.4  to  0.7  per  cent.),  and 
calculate  the  remainder  to  tannate  of  iron;  i  part  of  Fe2O3  =  7.2 
parts  of  ferric  tannate. 


266  THE   TEXTILE  FIBRES. 

Perhaps  the  most  accurate  method  of  analyzing  silk  for  total 
amount  of  weighting  is  to  determine  the  amount  of  nitrogen 
present  as  silk  by  Kjeldahl's  process.*  To  do  this  it  is  first  nec- 
essary to  remove  all  gelatin,  Prussian  blue,  or  other  nitrogenous 
matters.  This  is  effected  by  boiling  a  weighed  quantity  of  the 
silk  (about  2  grams)  with  a  2  per  cent,  solution  of  sodium  carbonate 
for  thirty  minutes.  The  silk  is  then  washed,  and  heated  to  60°  C. 
for  thirty  minutes  in  water  containing  i  per  cent,  of  hydrochloric 
acid,  and  afterwards  well  washed  in  hot  water.  This  treatment 
with  alkali  and  acid  should  be  repeated  until  the  sample  no  longer 
has  a  blue  color.  With  souple  or  ecru  silks,  ammonia  or  ammo- 
nium carbonate  should  be  used  instead  of  sodium  carbonate, 
and  the  silk  should  be  finally  boiled  for  an  hour  and  a  half  in  a 
solution  containing  25  grams  of  soap  per  litre.  After  this  prepara- 
tion the  nitrogen  determination  is  conducted  as  follows:  The 
sample  is  placed  in  a  round-bottomed  flask  of  hard  glass,  and 
treated  with  about  20  c.c.  of  strong  sulphuric  acid,  with  the  addi- 
tion of  a  single  drop  of  mercury.  The  flask  is  then  heated,  gently 
at  first,  and  then  to  a  vigorous  boil;  then  10  grams  of  potassium 
sulphate  are  added  and  the  boiling  continued  until  the  contents 
of  the  flask  are  clear  and  colorless.  The  contents  are  then 
washed  into  a  distilling-flask  and  connected  with  a  suitable  con- 
denser. By  means  of  a  tap-funnel  an  excess  of  caustic  soda 
solution  is  gradually  added,  together  with  a  little  sodium  sul- 
phide to  decompose  any  nitrogen  compounds  of  mercury  that 
may  have  been  formed.  Some  granulated  zinc  is  placed  in  the 
flask  to  prevent  bumping,  and  the  distillate  is  collected  in  a  meas- 
ured quantity  of  standard  acid,  which  takes  up  the  ammonia 
that  distils  over.  Excess  of  acid  is  determined  by  titration  with 
standard  alkali,  using  methyl  orange  as  an  indicator  of  neutral- 
ity. The  above  method  is  based  on  the  fact  that  when  silk  (in 
common  with  the  great  majority  of  other  nitrogenous  organic 
substances)  is  heated  with  concentrated  sulphuric  acid,  the  whole 
of  the  nitrogen  present  is  eventually  converted  into  ammonia. 
Air-dried  silk  with  u  per  cent,  of  hygroscopic  moisture  contains 

*  Gnehm  and  Blenner,  Rev.  Gen.  Mat.  Col.,  April,  1898. 


QUANTITATIVE  ANALYSIS   OF   THE   TEXTILE  FIBRES.       267 

17.6  per  cent,  of  nitrogen,  consequently  the  amount  of  true  silk 
in  a  sample  may  be  obtained  by  multiplying  the  percentage  of 
nitrogen  found  by  the  factor  5.68.  This  method  yields  very  accu- 
rate results  if  the  determination  of  the  nitrogen  is  carefully  con- 
ducted. 

A  method  for  the  determination  of  the  weighting  on  silk 
which  appears  to  be  capable  of  yielding  very  good  results  is  that 
suggested  by  Gnehm.*  It  depends  on  the  fact  that  the  silk 
fibre  does  not  appear  to  be  injured  by  treatment  with  either 
hydrofluosilicic  acid  or  hydrofluoric  acid.  The  method  is  car- 
ried out  as  follows :  About  2  grams  of  the  silk  to  be  tested  are  im- 
mersed, with  frequent  stirring,  for  one  hour  at  the  ordinary  tem- 
perature in  100  c.c.  of  a  5  per  cent,  solution  of  hydrofluosilicic 
acid.  The  treatment  is  then  repeated  with  100  c.c.  of  fresh  acid 
of  the  same  strength.  The  silk  is  then  washed  several  times 
with  distilled  water  and  dried.  The  loss  in  weight  corresponds 
to  the  amount  of  inorganic  weighting  materials  present.  This 
method  serves  very  well  with  silk  weighted  with  stannic  phos- 
phate and  silicate,  but  does  not  appear  to  be  suitable  for  the 
estimation  of  weighting  on  black-dyed  silks  containing  iron  salts. 
It  is  said  that  oxalic  acid  may  also  be  used  (Muller,  Zeits.  Farben- 
u.  Text.  Chem.,  1903,  160)  for  the  purpose  of  removing  the  inor- 
ganic weighting  materials  from  silk,  without  injury  to  the  silk 
fibre  itself. 

*  Zeits.  Farben-u.  Text.  Chem.t  1903,  209. 


APPENDIX  I. 

MICROSCOPIC  ANALYSIS   OF  FABRICS. 

HOHNEL  describes  the  following  method  employed  for  a  micro- 
scopic examination  of  textile  fabrics,  where  the  object  is  to  deter- 
mine not  only  qualitatively  the  character  of  fibres  composing 
them,  but  also  their  quantitative  amounts.  With  regard  to  the 
preliminary  qualitative  examination,  there  are  generally  only  a  few 
fibres  to  be  taken  into  consideration,  as  there  seldom  occur  in  the 
same  fabric  more. than  one  to  four  different  kinds  of  fibres.  As 
a  rule,  the  only  fibres  which  will  be  found  are  cotton,  linen,  hemp, 
jute,  ramie,  sheep's  wool,  goat-hair,  cow-hair,  angora,  alpaca, 
cashmere,  llama,  silk,  and  tussah  silk.  In  woolen  material 
there  are  also  cosmos  and  shoddy  to  be  considered. 

To  undertake  the  examination,  cut  off  a  sample  of  the  mate- 
rial 2  to  3  sq.  cm.  in  size,  and  separate  this  into  its  warp-  and  fill- 
ing-threads. The  sample  must  be  of  sufficient  size  to  include 
all  of  the  different  kinds  of  yarns  employed  in  the  weave.  Con- 
sequently in  the  case  of  large  patterns  it  has  to  be  rather  large. 
The  warp-  and  filling-threads  are  laid  next  to  each  other,  and  one 
of  each  kind  is  selected  to  serve  for  further  examination.  In  the 
simplest  case  there  is  only  one  kind  of  warp-thread  and  one  kind 
of  filling  present,  which  necessitates,  therefore,  the  examination 
of  only  two  different  yarns.  In  complicated  cases  there  may  be 
as  many  as  ten,  or  even  more,  different  yarns  to  analyze.  In 
woolen  fabrics  there  will  frequently  be  found  yarns  which  are 
composed  of  two  or  three  different  threads  twisted  together; 
these  must  be  untwisted  and  each  separate  yarn  examined  by 
itself.  In  order  to  attain  satisfactory  results,  the  operator  must 
be  sufficiently  skilled  in  the  microscopy  of  the  fibres  to  be  able  to 
recognize  with  certainty,  under  a  low  magnification,  the  different 

269 


2 ?o  APPENDIX  I. 

fibres  liable  to  be  found.  By  a  low  magnification  is  meant  one 
of  fifty  to  sixty  times.  A  much  higher  power  cannot  be  used  in 
the  examination  of  fabrics,  for  hundreds  or  even  thousands  of 
fibres  have  to  be  taken  into  consideration.  From  ten  to  twenty 
fibres,  or  perhaps  more,  should  be  obtained  in  the  field  at  the 
same  time,  and  it  is  necessary  to  be  able  to  promptly  recognize 
the  different  ones.  With  a  higher  magnification,  it  is  true,  the 
single  fibres  can  be  better  recognized,  but  the  general  view  is 
then  lost,  and  there  is  danger  in  overlooking  whole  bundles  of 
fibres.  If  the  observer  finds  a  fibre  which  cannot  be  recognized 
with  sufficient  accuracy  by  means  of  the  low  power,  it  is  a  simple 
matter  to  so  change  the  objective  as  to  increase  the  magnification 
to  allow  of  the  necessary  observations  to  be  made,  and  then  to 
proceed  again  with  the  examination  under  the  lower  power. 

Dark  colored  material  often  consists  for  the  most  part  of 
threads  which,  on  microscopic  examination,  appear  quite  opaque, 
hence  dark  and  structureless.  Therefore  it  will  frequently  be 
necessary  to  remove  the  dyestuff,  at  least  in  part,  which  is  usually 
done  by  boiling  in  acetic  acid,  hydrochloric  acid,  dilute  caustic 
alkali,  potassium  carbonate,  etc.,  until  sufficiently  light  in  appear- 
ance. 

In  the  case  of  very  accurate  examinations,  each  different  kind 
of  thread  must  be  examined  separately,  and  the  number  of  fibres 
composing  it,  together  with  their  kind  and  color,  must  be  noted. 
In  order  to  show  the  detail  and  scope  of  such  an  examination,  the 
following  example  is  given:  On  unravelling  a  sample  four  differ- 
ent warp-threads  and  one  filling-thread  were  obtained.  One  of 
the  warp-threads  was  composed  of  two  yarns  twisted  together, 
one  of  which  was  black  (K^)  and  the  other  white  (KJ)). 
Two  warp-threads  were  dark  blue  (K2  and  K3)  and  the  fourth 
was  a  gray  mix  (K4) ;  the  filling-thread  (£)  was  blue.  On  exam- 
ination the  following  results  were  obtained: 

K^a  showed  85  shoddy  fibres  (mostly  black,  some  yellow  and 
red,  and  even  isolated  green  fibres  of  wool,  and  13  cotton  fibres). 

KJ)  showed  31  pure  white  wool  fibres. 

K2  and  K3,  respectively,  showed  46  and  53  pure  blue  wool 
fibres. 


MICROSCOPIC  4NJLYSIS  OF  FABRICS.  271 

K4  showed  60  shoddy  fibres,  of  which  32  were  mostly  gray  or 
black  wool  fibres,  and  28  were  gray  cotton  fibres. 

E  showed  60  blue  wool  fibres. 

Therefore  in  this  sample,  including  4  warp-  and  4  filling- threads, 
there  would  be  85  +  31  +  46+53  +  60=275  single  warp  fibres; 
and  60X4=240  filling  fibres;  or  515  single  fibres  altogether.  Of 
these  41  were  cotton,  which  were  found  in  the  shoddy,  the  latter 
comprising  145  fibres  in  all.  Hence  in  a  sample  of  this  piece  of 
goods  containing  equal  lengths  of  warp  and  weft,  there  are  41 
cotton  fibres,  104  shoddy- wool  fibres,  and  370  pure- wool  fibres, 
from  which  the  respective  percentages  would  be : 

PerCent. 

Cotton 8.0 

Shoddy- wool 20 . 2 

Pure-wool 71.8 

100.0 

This,  of  course,  only  gives  the  relative  percentages  of  the 
number  of  fibres;  if  it  is  desired  to  reach  an  approximate  idea  of 
the  proportions  by  weight,  then  micrometric  measurements  must 
be  made  of  the  wool  and  cotton  fibres  occurring  in  the  sample. 
In  consideration  of  the  fact  that  wool  possesses  about  twice  the 
cross-section  of  cotton,  it  becomes  a  rather  easy  matter  to  calcu- 
late the  ratio  between  the  two,  by  means  of  which  the  percentage 
by  weight  can  be  readily  obtained,  provided  that  the  specific 
gravity  of  wool  is  taken  to  be  about  the  same  as  that  of  cotton, 
which  is  approximately  true. 


APPENDIX  II. 

MACHINE  FOR  DETERMINING  STRENGTH  OF  FIBRES. 

THERE  have  been  a  number  of  machines  devised  for  the  pur- 
pose of  determining  the  tensile  strength  and  elasticity  of  fabrics 
and  yarns,  and  a  few  instruments  have  also  been  adapted  for 
the  testing  of  single  fibres.  As  the  individual  fibre,  however,  is 
a  very  slender  and  delicate  object,  especially  in  the  case  of  cer- 
tain vegetable  fibres,  the  determination  of  its  physical  factors  is 
an  operation  which  requires  a  delicately  adjusted  apparatus.  In 
machines  which  require  the  taking  on  or  off  of  weights,  the  jar  is 
usually  sufficient  to  break  the  fibre  before  its  true  breaking  strain 
is  reached.  The  same  criticism  is  also  true  for  machines  employ- 
ing water  as  a  weight.  A  machine  devised  for  the  use  of  the 
Philadelphia  Textile  School  has  proved  very  satisfactory  for 
determining  the  tensile  strength  and  elasticity  of  almost  any 
fibre,  from  very  fine  and  delicate  filaments  to  coarse  and  strong 
hairs.  A  diagrammatic  drawing  of  this  machine  is  given  in  Fig. 
69.  The  fibre  to  be  tested  is  clamped  between  the  jaws  at  (/), 
the  pointer  attached  to  the  end  of  the  beam  above  the  upper  jaw 
being  brought  to  the  zero- mark  on  the  scale  (5),  while  the  lower 
jaw  is  raised  or  lowered  in  its  stand  until  the  desired  distance 
between  the  jaws  is  obtained.  To  obtain  comparable  results  this 
distance  should  always  be  the  same;  and  10  cm.,  in  the  case  of 
long  fibres,  or  2  cm.  for  short  fibres,  have  proved  to  be  good 
lengths  of  fibre  to  test.  The  sliding-bar  (R)  is  moved  forward  by 
turning  the  rod  (7"),  which  moves  the  rack  and  pinion  at  (P), 
until  the  graduation  on  the  wheel  (G)  is  at  zero  to  the  indie  ;i lor. 

Under  these  conditions  there  is  no  strain  on  the  fibre.     A  stretch- 

272 


MACHINE  FOR  DETERMINING  STRENGTH  OF  FIBRES.       273 

ing-force  is  then  placed  on  the  fibre  by  moving  the  bar  (R)  back- 
ward by  turning  the  rod  (T)\  the  motion  of  this  bar  is  made 
uniform  and  gradual  until  the  fibre  finally  breaks  under  the  strain 
thus  placed  upon  it.  The  graduation  on  the  wheel  (G)  will 
then  indicate  in  decigrams  the  breaking  strain  of  the  fibre  being 
tested.  The  elasticity  is  obtained  by  watching  carefully  the 
pointer  moving  up  the  scale  of  millimeters  at  (S)  until  the  rupture 


FIG.  69. — Fibre-testing  Machine  of  Reeser  &  Mackenzie. 

/,  jaws  with  screw-clamps  for  holding  the  fibre;  the  lower  jaw  may  be  raised  or 
lowered;  R,  sliding-rod  working  on  a  rack  and  pinion;  this  takes  the  place 
of  weights;  G,  wheel  graduated  on  its  face  in  decigrams,  moving  on  the 
same  axis  as  the  pinion  for  sliding  the  weight;  71,  thumb-screw  for  turning 
the  small  shaft  working  the  pinion  at  P;  W,  counterbalancing  weight  for 
regulating  the  zero-point  of  the  machine;  S,  scale  for  reading  the  stretch  of 
the  fibre. 

of  the  fibre  takes  place ;  the  distance  this  pointer  moves  represents 
the  actual  stretch  of  the  fibre;  and  if  the  length  of  fibre  taken 
between  the  jaws  is  10  cm.,  this  figure  will  represent  directly  the 
percentage  of  elasticity.  If  the  length  of  fibre  taken  is  only  2  cm., 
to  obtain  the  percentage  of  elasticity  it  is  necessary  to  multiply 
the  amount  of  stretch  in  millimeters  by  five ;  and  for  other  lengths 
of  fibre  similar  proportions  will  hold.  The  weight  (W)  at  the 
rear  end  of  the  beam  can  be  moved  backward  or  forward,  and 
is  for  the  purpose  of  adjusting  the  balance  so  that  there  is  no 
strain  at  (/)  when  the  indicator  on  (G)  marks  zero.  The  wheel 


274  APPENDIX  II. 

(G)  is  graduated  in  decigrams,  and  this  marks  the  sensibility  of 
the  machine;  the  total  graduations  on  (G)  running  from  zero  to 
400.  When  fibres  are  tested  having  a  greater  tensile  strength 
than  400  decigrams  a  fixed  additional  weight  of  10,  25,  50,  etc., 
grams  may  be  hung  from  (W),  and  this  must  be  added  to  the 
reading  on  the  wheel  when  the  fibre  breaks.  If  the  elasticity  of 
the  fibre  is  so  great  as  to  carry  the  pointer  beyond  the  limits  of 
the  scale  at  (5),  a  shorter  length  of  fibre  must  be  tested.  A  fair 
average  of  breaking  strain  and  elasticity  may  be  obtained  for 
any  quality  of  fibre  by  testing  about  10  separate  fibres  and  taking 
a  mean  of  the  total  tests.  If  the  quality  of  the  fibres,  however, 
in  a  sample  does  not  run  very  uniform,  it  is  best  to  increase  the 
number  of  tests  to  25  or  even  50  in  order  that  a  satisfactory 
average  may  be  obtained. 

This  machine  is  capable  of  being  used  with  all  classes  of  fibres, 
and  its  results  are  very  satisfactory,  as  has  been  proved  by  several 
years'  use  at  the  Philadelphia  Textile  School.* 

*  This  machine  is  made  by  Reeser  &  Mackenzie  of  Philadelphia. 


APPENDIX   III. 

BIBLIOGRAPHY   OF  THE  TEXTILE   FIBRES. 

Allen.     Commercial  Organic  Analysis,  vol.  I,  and  vol.  in,  part  m. 

Philadelphia,  1898. 
Berthold.     Ueber    die    mikroskop.     Merkmale    der    wichstigen 

Pflanzenfasern.     1883. 
Bolley.     Beitrage  zur  Theorie  der  Farberei. 
Bolley.     Untersuchung  ueber  die   Yamamayseide.     Polyt.   Zeit- 

schrift,  1869,  p.  142. 
Bolley   and   Schoch.     Ueber   die    Seiden.     Dingl.    Polyt.   Jour., 

1870,  p.  72. 
Biesiadecky.     Artikel   Haut,    Haare,    und   Naegel   in    Strieker's 

Handbuch  der  Lehre  von  den  Geweben.     Leipzig,  1871. 
Browne.     Trichologia  mammalium.     Philadelphia,  1853. 
Bottler.     Die  vegetabilischen  Faserstoffe.     Leipzig,  1900. 
Bottler.     Die  animalischen  Faserstoffe.     Leipzig,  1902. 
Bowman.     The  Structure  of  the  Wool  Fibre. 
Bowman.     The  Structure  of  the  Cotton  Fibre. 
Beech.     Dyeing  of  Cotton  Fabrics,  pp.  1-22.     London,  1901. 
Beech.     Dyeing  of  Woolen  Fabrics,  pp.  1-14.     London,  1902. 
Cross  and  Bevan.     Cellulose.     London,  1895. 
Cross  and  Bevan.     Researches  on  Cellulose,  1895  to  1900.     Lon- 
don, 1901. 

Cross  and  Bevan.     Paper  Making,  pp.  i-no.     London,  1900. 
Christy.     New  Commercial  Plants  and  Drugs.     1882. 
Cuniasse  et  Zwilling.     Essais  du  Commerce;    Matieres  textiles, 

pp.  225-232.     Paris,  1901. 

275 


27<5  APPENDIX  III. 

Clark.     Practical  Methods  in  Microscopy.     Boston,  1900. 
Dodge.     Descriptive  Catalogue  of  the  Useful  Fibre  Plants  of  the 

World.     Report  No.  9  of  the  U.  S.  Dept.  of  Agriculture. 

1897. 

Dodge.     Report  on  Flax  Culture.     No.  10,  U.  S.  Dept.  of  Agri- 
culture.    1898. 

Eble.  Die  Lehre  von  die  Haaren.  2  vols.  Vienna,  1831. 
Engel.  Ueber  das  Wachsen  abgeschnittener  Haare.  1856. 
Erdl.  Vergleichende  Darstellung  des  inneren  Baues  der  Haare. 

1841. 

Editors  of  the  "Dyer  and  Calico  Printer."     Mercerisation.     Lon- 
don, 1903. 

Frey.     Das  Mikroskop  fur  Aerzte,  etc. 
Grothe.     "  Textil  Industrie  "  in  Muspratt's  Chemie,  vol.  v. 
Gurlt.     Vergleichende  Untersuchungen  ueber  die  Haut.     Berlin, 

1844. 

Gardner.     Die  Mercerisation  der  Baumwolle.     Berlin,  1898. 
Garden.     Wool  Dyeing,  part  I,  pp.  7-19.     Philadelphia,  1896. 
Georgevics.     Chemical  Technology  of  the  Textile  Fibres.     Trans. 

Salter.     London,  1902. 
Gnehm.     Taschenbuch   fur   die    Farberei   und    Farbenfabriken : 

"  Gespinnstfasern,"  pp.  1-17.     Berlin,  1902. 
Hummel.     Dyeing  of  the  Textile  Fibres.     London,  1896. 
Hannan.     Textile  Fibres  of  Commerce.     London,  1902. 
Hohnel.     Die   Mikroskopie   der   technische   verwendeten   Faser- 

stofle.     Leipzig,  1887. 
Hohnel.     Die    Unterscheidung    der    pflanzlichen    Textilfasern. 

Dingl.  Polyt.  Jour.,  CCXLVI,  465. 

Hohnel.     Ueber  pflanzliche  Faserstoffe.     Vienna,  1884. 
Hohnel.     Ueber  den  Bau  und  die  Abstammung  der  Tillandsia- 

faser.     Dingl.  Polyt.  Jour.,  ccxxxiv,  407. 
Hohnel.     Beitrage  zur  technischen  Rohstofflehre.     Dingl.  Polyt. 

Jour.,  CCLII. 
Hoyer.     Das  Papier,   seine/Beschaffenheit  und  deren  Priifung. 

Muenchen,  1882. 
Hanausek  und  Nebeski.     Mikroskopie  von  Pelzhaaren.     Jahres- 

bericht  der  Wiener  Handelsakademie.     1884. 


BIBLIOGRAPHY  OF   THE    TEXTILE  FIBRES.  277 

Halphen.  La  Pratique  des  Essais  commerciaux  et  industriels 
Matieres  organiques.  "  Textiles  et  Tissues,"  pp.  326-342. 
Paris,  1893. 

Heermann.  Dyers'  Materials:  "Textile  Fibres,"  pp.  16-24. 
Trans.  Wright.  London,  1900. 

Janke.     Wool  production.     1864. 

Joclet.     Chemische  Bearbeitung  der  Schafwolle.     Leipzig,  1902. 

Knecht,  Rawson,  and  Loewenthal.  Manual  of  Dyeing,  vol.  I, 
pp.  1-57.  London,  1893. 

Karmarsh.  Technisches  Worterbuch.  Artikel  "  Baumwolle  "  und 
"Gespinnstfasern."  1876. 

Kolliker.     Handbuch  der  Gewebelehre. 

Leydig.     Lehrbuch  der  Histologie. 

Lafar.     Technical  Mycology,  vol.  I.     London,  1898. 

Lunge.  Chemische  technische  Untersuchungsmethoden,  vol.  in, 
pp.  1026-1056.  Berlin,  1900. 

Monie.     The  Cotton  Fibre.     London,  1890. 

Nathusius-Konigsborn.  Das  Wollhaar  des  Schafes  in  histolo- 
gischen  und  technischen  Beziehung.  Berlin,  1866. 

Orschatz.  Ueber  den  Bau  der  wichtigsten  verwendbaren  Faser- 
stoffe.  Polyt.  Centralblatt,  p.  1279.  1848. 

Rohde.  Beitrage  zur  Kenntniss  des  \Vollhaares.  Eldenaer 
Archiv.  1856,  1857. 

Rawson,  Gardner,  and  Laycock.  Dictionary  of  Dyes,  Mor- 
dants, etc.;  articles  relating  to  Textile  Fibres.  London, 
1901. 

Schlesinger.  Examen  microscopique  et  microchemique  des  Fibres 
textiles.  Paris,  1875. 

Schacht.  Die  Priifung  der  im  Handel  vorkommenden  Gewebe. 
Berlin,  1853. 

Schmidt.     Schafzucht  und  Wollkunde.     1852. 

Silvern.     Die  ktinstliche  Seide.     Berlin,  1900. 

Sadtler.  Handbook  of  Industrial  Organic  Chemistry.  Phila- 
delphia, 1897. 

Sansone.  Dyeing  Wool,  Silk,  Cotton,  etc.,  vol.  I,  pp.  18-32. 
London,  1888. 

Sansone.     Printing  of  Cotton  Fabrics,  pp.  53-73.     London,  1001. 


278  APPENDIX  III. 

Thorpe.     Dictionary  of  Applied  Chemistry;    articles  relating  to 

Textile  Fibres.     New  York,  1895. 
United   States   Report.     The    Cotton   Plant.     Bulletin   No.  38, 

Dept.  of  Agriculture,  1896. 

Vetillard.     foudes  sur  les  Fibres  vege'tales  textiles.     Paris,  1876. 
Vignon.     La  Soie.     Paris,  1890. 
Witt.     Chemische    Technologic    des    Gespinnstfasern,     part    I. 

Braunschweig,  1891. 
Wiesner.     Die  Rohstoffe  des  Pflanzenreiches,  vol.  n,  "  Fasern." 

Leipzig,  1903. 
Wiesner.     Beitrage  zur  Kenntniss  der  indischen  Faserpflanzen. 

1870. 

Wiesner.     Einleitung  in  die  technische  Mikroskopie.     1867. 
Wiesner  und  Prasch.     Ueber  die  Seiden,  in  Mikroskop.     Unter- 

suchungen,  1872,  p.  45;    und  Dingl.  Polyt.  Jour.,  p.  190. 

1868. 

Wagner.     Handbuch  der  Physiologic.    Artikel  "Der  Haut" 
Wagner.     Chemical  Technology:  "  Fibres,"  pp.  798-871.     Trans. 

Crookes.     New  York,  1897. 
Wertheim.     Ueber  den  Bau  des  Haarbalges.     Vienna,  1864. 


INDEX. 


Abaca  fibre,  202 
Abelmoschus  tetraphyllos,  99 
Abutilon  avicenna,  184 
Acid-proof  fabrics,  172 
Adamkiewitz's  test  for  proteids,  88 
Adipocelluloses,  146 
African  cottons,  119,  125,  127 
African  sheep,  7 
Agave  americana,  100,  203 
decipius,  192 
j&tida,  192 
heteracantha.  192 
rigida,  192,  203 
Agerian  cotton,  125 
Ailanthus  silk,  74 

action  of  polarized  light  on,  223 
Alabama  cotton,  127 
Alkali-cellulose,  145*  X57 
Allanseed  cotton,  126 
Aloe  fibre,  203 

hemp,  239,  242 
Aloe  perfoliata,  99,  109 
Alpaca,  6,  59 

microscopy  of,  60 
Ambari  hemp,  191,  i98 
American  cotton,  varieties  of,  126 
merino  wool,  15 
wools,  shrinkage  of,  25 
Amido-cellulose,  152 
Amido  group  in  wool,  evidence  of,  35 
Ammoniacal   nickel   oxide   solution    for 

fibre -testing,  211 
Amyloid,  144 
Angola  sheep,  7 
Angora  goat,  6 
Animal  and  vegetable  fibres,  distinction 

between,  2 
Animal  fibres,  i 

Lieberman's  test  for,  212 
Animalized  cotton,  175 
Antheraa  assama,  74 
mylitta,  74 
pernyi,  74,  222 
yama-mai,  74 


Antiphlogin,  171 
Apocynum  cannibinum,  192 
Argali,  6 

Arryndia  ricini,  222 
Artificial  fibres,  i 

classification  of,  3 
horse -hair,  148 
silks,  4 

chemical  reactions  of,  175 
comparison  of,  174 
identification  of,  217,  220 
manufacture  of,  171 
tensile  strength  of,  175 
wool,  50 
Asbestos,  2 

Asclepias  cornutii,  228,  243 
cotton,  122 

curassavica,  122,  228,  244 
Ash  in  various  cottons,  141 
of  cotton,  analysis  of,  141 
of  jute,  analysis  of,  186 
of  wool  fibre,  analysis  of,  34 
Assam  cotton,  128 
Attacus  atlas,  74 
lunula,  222 
ricini,  74 

Auchenia  huanaco,  61 
llama,  61 
paco,  59 
viccunia,  61 

Australian  botany  wool,  15 
cotton,  127 

B. 

Bahia  cotton,  126 

Bamboo  papers,  105 

Barbadoes  cotton,  115 

Barwall  sheep,  7 

Basinetto  silk,  72 

Bass  fibres,  104 

Bast  fibres,  97,  100,  106,  232 

reactions  of,  217,  218 

structure  of,  98 
papers,  105 
Bastose,  185,  186 


279 


280 


INDEX. 


B-iuhiniii  racenwsa,  99,  109 

Bave,  73 

Bearded  sheep  of  west  Africa,  7 

Beard-hair  of  sheep,  8 

Beaumont  ia  grandiftora,  122,  228 

Benders  cotton,  127 

Bengal  cotton,  119,  125,  128 

hemp,  191 

Bhownuggar  cotton,  128 
Bibliography  of  the  textile  fibres,  275 
Big-horn  sheep,  6 
Bilatee  cotton,  128 
Biuret  test  for  proteids,  88 
Black-faced  sheep  of  Thibet,  7 
Black-fellows  hemp,  191 
Bcehmeria  nivea,  99,  188 

tenacissima,  99,  188 
Boiled-off  liquor,  85 

use  of,  8 1 

"  Bolton  counts,"  116 
Bombax  ceiba,  121,  231 

cotton,  121,  244 

heptaphyllum,  09,  121,  231 

mal  aba  ricum,  121 

pentandrum,  121 
Bombay  hemp,  191 
Bombyx  mori,  69 
Bourbon  cotton,  128 
Bourette  silk,  84 
Boweds  cotton,  127 
Bowstring  hemp,  191 
Brazilian  cotton,  varieties  of,  126 

sheep,  7 
Brins,  73 

Broach  cotton,  119,  125,  127 
Broad-tailed  sheep,  7 
Bromelia  karatas,  99,  100,  109 

pinguin,  100 
Broom  fibres,  104 
Broom-grass  fibre,  too 
Brown  Egyptian  cotton,  119,  125,  126 

hemp,  191 
Brush  fibres,  103 

C. 

Cago  sheep,  7 
Calabria  cotton,  1 28 
Calcium  pectate,  179 
Calcutta  hemp,  191 
Calotropis  gigantea,  99,  109,  122,  228 

procera,  228,  243 
Camel's  hair,  62 
Cannabis  gigantea,  192 

saliva,  90,  too,  192 
Carbohydrates,  143 
Carbonization  of  wool -silk  goods>  31 
Carbonizing,  ;i 
Carthagenian  cotton,  127 
Cashmere,  6,  57 
Cat-hair,  65 


Caulking  fibres,  105 

Caustic  alkali   solution  for  fibre-testing, 
211 

soda,  absorption  of  wool  for,  35  • 

action  of,  on  wool,  39 
Ceara  cotton,  120,  125,  126 
Cebu  hemp,  191 
Ceiba  cotton,  231 

Cells  of  wool  fibre,  dimensions  of,  19 
Celluloid,  150 
Cellulose,  142 

chemical  constitution  of,  144 

properties  of,  143 

acetate,  145 

benzoate,  146 

hydrate,  156 

nitrate,  146 

sulphate,  146 

tetracetate,  146 

thiocarbonate,  145 

xanthate,  145 
Chappe  silk,  84 
Chardonnet  silk,  171 
Chemical  analysis  of  cloth,  248 

yarn,  250 

China-grass,  99,  109,  188,  233 
Chinese  cotton,  114,  121,  125,  127 

jute,  184 

sheep,  7 
Chlored  wool,  applications  of,  41 

preparation  of,  42 

properties  of,  41 
Cholesterol,  33 
Chorisia  spcciosa,  121 
Cibotium  glcmcum,  122 
Classification  of  fibres,  i 
Cocoanada  cotton,  128 
Cocas  nucijera,  100 

Cochineal  tincture  for  fibre-testing,  209 
Cochlospernum  gossypium,  244 
Cpcons  silk,  72 

Coefficient  of  acidity  of  various  fibres,  35 
Coir  fibre,  99,  100,  241 

uses  of,  207 
Collodion,  150 

silk,  172 

Colorado  river  hemp,  191 
Coloring-matter  in  cotton,   140 

wool,  34 
Common  hemp,  192 

sheep,  o 

Commcrsonia  jrasrri,  191 
Compound  celluloses,  146 
Comptah  cotton,  i  KJ,  125,  127 
Conditioning  apparatus,  47 

houses,  45 

of  wool,  45 
Congo  sheep,  7 
Copper  sulphate  solution  for  fibre-testing, 


INDEX. 


281 


Corchorus  capsularis,  99,  100,  184 
decemangnlatus,  184 
juscus,  184 
o  itorius,  99,  184 
Cordage  fibres,  103 

strength  of,  197,  207 
Cor dia  lati folia,  99,  109 
Cortical  layer  in  wood  fibre,  19 
Corypha  nmbraculijera,  IOO 
Cosmos  fibre,  51 
Cotted  fleeces,  32 
Cotton,  99,  109,  225,  233,  243 
action  of  alkalies  on,  151 
ammonia  on,  152 
coloring-matters  on,  154 
heat  on,  147 
metallic  salts  on,  154 
mineral  acids  on,  149 
organic  acids  on,  151 
oxidizing  agents  on,  154 
sulphides  on,  153 
tannin  on,  151 
chemical  reactions  of,  147 
dry  distillation  of,  147 
effect  of  bleaching  on,  155 
fermentation  of,  154 
origin  and  growth  of,  no 
., physical  structure  of,  124 
~  and  linen,  distinction  between,  213 
fibre,  capillarity  of,  124 
chemical  properties  of,  139 
conditions   determining   quality   of, 

114 

diameter  of,  125,  129 

length  of,  125,  129 

microscopic  properties  of,  132 

mineral  matter  in,  139 

number  of  twists  in,  124 

physiological  development  of,  112 

staple  of,  130 

structure  of,  131 
Cotton-grass,  106,  225 
Cotton-oil,  139 
Cotton  plant,  no 
Cotton-silk,  123 
Cotton-tree,  121 
Cotton-wax,  139 

analysis  of,  140 
Cotton-wool,  99 
Count  of  cotton  yarn,  117 
Courtrai  flax,  178 
Cow-hair,  58,  62 

microscopy  of,  64 

Chromic  acid,  action  of,  on  wool,  37 
Cretan  hemp,  192 

sheep,  6 

Crimean  sheep,  7 
Crotolaria  juncea,  99,  100,  191,  192 

tennifolia,  192 
Cryptostemma  calendulaceum,  224 


Cryptostemma  hairs,  225 
Cuba  bast,  103 
Cuban  hemp,  192 
Curumbar  sheep,  7 
Cutose,  1 06,  147 
Cycadce  macrozamia,  224 

D. 

Dacca  cotton,  115 

Datisca  cannabinus,  192. 

Dea  cotton,  115 

Dead  cotton,  124,  133 

Deccan  sheep,  7 

Deniers,  comparison  of  the  different,  73 

Dew-retting  of  flax,  178 

Dhanvar  cotton,  119,  127 

Dhollera*h  cotton,  125,  128 

Diazotized  wool,  37 

acid  number  of,  38 

action  of  phenols  on,  38 

iodin  number  of,  38 
Dicotyledonous  fibres,  97,  236 
Distinction  between  animal  and  vegetable 

fibres,  208 
Domestic  sheep,  7 
Dukhun  sheep,  7 
Du  Vivier's  silk,  171 

E. 

East  Indian  cotton,  127 
Echappe  silk,  84 
Edisto  cotton,  125,  126 
Edredon  vegetal,  121 
Egyptian  cotton,  115 

varieties  of,  126 
Elairerin,  33 
Rlais  guinensis,  100 
Elasticity  of  wool  fibre,  20 
Elephant-grass,  106 
Eriodendron  aufractuosum,  121,  231 
Eriophorum  angustifolium,  225 

lati/olium,  225 
Esparto  fibre,  109 

grass,  99,  100,  236 
Eupatorium  cannabinum,  192 
Extract  wool,  50 

F. 

Fabric  fibres,  102 

Fagara  silk,  74 

False  hemp,  192 
sisal  hemp,  192 

Feather-grass  fibre,  100 

Fehling's  solution,  preparation  of,  259 

Ferric    sulphate    solution    for    fibre-test- 
ing, 211 

Fezzan  sheep,  7 

Fibre-testing  machine,  272 


282 


INDEX. 


Fibroin,  85 

action  of  nitrous  acid  on,  88 

amount  of  in  raw  silk,  87 

chemical  composition  of,  87 

chemical  properties  of,  88 

manner  of  preparing  pure,  87 

structure  of,  79 
Fiji  cotton,  118,  126 
Fitschi  cotton,  125 
Flax,  99,  232 

Belgian,  109 

character  of  wax  in,  182 

cellulose,  isolation  of  pure,  180 

fibre,  analysis  of,  182 
bast  cells  of,  181 
color  of,  1 80 

distinction  of  from  hemp,  18^ 
filaments,  dimensions  of,  180 
Flax-seed,  use  of  for  oil,  177 
Florette  silk,  84 
Florida  cotton,  118,  125,  126 
Floss  silk,  72 
Frisonnets  silk,  72 
Prisons  silk,  72 

Fuchsine  solution  for  fibre-testing,  209 
Fungoid  growth  on  wool,  42 
Fur,  6 
Furcrasa  cubensis,  192 

G. 

Galletame  silk,  72 

Gallini  cotton,  118,  125,  126 

Gambo  hemp,  100,  198,  237,  245 

Garar  sheep,  7 

Georgia  cotton,  125 

Giant  hemp,  192 

Ginning,  in 

Glass  wool,  3 

Goat-hair,  58 

difference  of  from  wool,  8 
Goitred  sheep,  7 
Gossypium  acuminatum,  99 

album,  114 

arboreum,  99,  114,  115,  116 

barbadeuse,  99,  114,  115,  117 

braziliense,  114 

chinese,  114 

cochlospernum,  121,  231 

conglomeratum,  99 

croceum,  114 

egliinduhsum,  114 

elatum,  114 

jructescens,  114 

fuse urn,  1 14 

glabrum,  114 

glandulosum,  114 

herbaceum,  99,  114,  115,  116,  119 

hirsutum,  115,  116,  120 

indie  urn,  115 


Gossypium  jamaicense,  115 

javanicum,  115 

latijolium,  115 

leoninum,  115 

macedonicum,  115 

maritinum,  115 

micranthum,  115 

molle,  115 

^tanking,  115 

ne gleet  um,  115 

nigrum,  115 

obtusifolium,  115 

oligospernum,  115 

paniculatum,  115 

perenne,  115 

perin'ianum,  115,  116,  120 

punctatum,  115 

racemosum,  115 

religiosum,  115,  121 

roxburghianum,  115 

sandwichense,  116 

siamense,  115 

sinense,  115 

strictum,  115 

stocksii,  115 

tahitense,  116 

tomentosum,  115 

tricuspidatum,  115 

vitifolium,  115 

wightianum,  115 
Greek  cotton,  127 
Grege,  83 
Guinea  sheep,  7 
Guncotton,  150 


H. 


Hair,  wool  as  a  variety  of,  6 

follicle,  10 
Hayti  hemp,  192 
Hemp,  99,  191,  234,  246 

fibre,  analysis  of,  197 
microscopy  of,  194 
uses  of,  197 

geographical  distribution  of,  192 
Hexanitro-cellulose,  150 
Hibiscus  cannabinus,  99,  100,  109,  191 

sabdariffa,  192 
Hindoostan  dumba  sheep,  7 
Hingunghat  cotton,  119,  125,  127 
Heloptelia  integri folia,  99 
Hooniah  sheep,  7 
Hop  fibre,  100 
Horse-hair,  64 
Hoy  a  viridi flora,  228 
Ilumulus  lupulus,  100 
Hydrocellulose,  145 

Hydrochloric  acid,  action  of,  on  wool,  37 
Hygroscopic  moisture  in  various  fibres,  45 


INDEX. 


283 


I. 

Ife  hemp,  192 

Imido-group  in  wool,  evidence  of,  35 
Imitation  metallic  threads,  4 
Indian  cotton,  125 

hemp,  192 

sheep,  7 

lodin  solution  for  fibre-testing,  212 
Isocholesterol,  33 
Italian  cotton,  128 

J. 

Javanese  sheep,  7 

John  Isle  cotton,  125 

Jubbulpore  hemp,  192 

Jute,  09,  loo,  109,  184,  237 

Jute-butts,  188 

Jute  cellulose,  isolation  of  pure,  185 
fibre,  action  of  bleaching  on,  187 
analysis  of,  186 
microscopy  of,  185 
physical  properties  of,  188 
preparation  of  from  plant,  184 
uses  of ,i 88 


Kapok,  121 
Kemps,  23 
Keratin,  30 
Khandeish  cotton,  128 
Kidney -cottons,  114 
Kittul  fibre,  104 
Kurrachee  cotton,  128 
Kydia  calycina,  99 


Lace-barks,  103 
Lace  fibres,  103 
La  Guayran  cotton,  127 
Lagetta  lintearia,  100 
Lagos  cotton,  127 
Lamb's  wool,  16 
Lanuginic  acid,  35 

analysis  of,  36 

preparation  of,  36 

properties  of,  36 
Laportea  gigas,  192 
Lasoisyphon  speciosus,  99 
Layer  blasts,  103 

Lead  acetate  solution  for  fibre-testing,  211 
Leaf  fibres,  234 
Levant  cotton,  128 
Lehncr  silk,  171 

Ligneous  matter,  detection  of,  216 
Lignocelluloses,  146 
Linden-bast,  99,  100 
Linen,  100,  232,  246 


Linum  angustifolium,  177 

commun,  177 

luvisii,  177 

usilatissimum,  99,  177 
Linters  cotton,  127 
Llama,  59 

fibre,  microscopy  of,  61 

goat,  6 

Louisiana  cotton,  125 
Lustra -cellulose,  170 
Lustre  of  wool  fibre,  agencies  affecting,  18 

cause  of,  18 

Lustring  cotton  with  engraved  rollers,  169 
LygcBum  spartum,  100 

M. 

Maceio  cotton,  120,  125,  126 

Madagascar  sheep,  7 

Madder  tincture  for  fibre-testing,  209 

Madras  cotton,  125,  128 

Majagua,  224 

Manila  hemp,  100,  109,  192,  201,  239,  242 

analysis  of,  202 
Many-horned  sheep,  7 
Maoutia  puya,  192 
Maranhams  cotton,  120,  125,  126 
Margaric  acid,  140 
Marrow  of  wool  fibre,  21 
Mauritia  flexuoso,  100 
Mauritius  hemp,  203 
Medulla  of  wool  fibre,  21 

function  of,  22 
Meliotus  alba,  100 
Memphis  cotton,  127 
Menouffieh  cotton,  126 
Mercerized   cotton,    conditions   affecting 

lustre  of,  159 
method  of  washing,  165 
microscopy  of,  168 
properties  of,  167 
scroop  of,  165 

strength  and  elasticity  of,  160 
wool,  preparation  of,  40 

properties  of,  40 
Mercerizing,  153,  156 

action  of  caustic  soda  in,  163 
character  of  fibre  for  use  in,  165 
chemicals  employed  for,  161 
conditions  for  best,  161 
effect  of  tension  in,  163 
Herbig's  experiments  on,  164 
patents  concerning,  167 
temperature  of,  162 
in  pattern,  166 
Merino  sheep,  6,  9 
Metacellulose,  147 
Metallic  threads,  4 
Microscopic  analysis  of  fabrics,  269 
Mildew  on  cotton,  154 
wool,  42 


284 


INDEX. 


Millon's  reagent,  preparation  of,  88,  211 

test  for  proteids,  88 
Mineral  fibres,  i 
Minor  hair  fibres,  64 
Mississippi  cotton,  125 
Mitafiffi  cotton,  126 
Mixed  fibres,  analysis  of,  217,  219,  254 
Mobile  cotton,  120,  125,  127 
Mohair,  6,  55 

difference     between     domestic     and 
foreign,  56 

microscopy  of,  56 

Molisch's  test  for  vegetable  fibre,  212 
Monkey  bass,  104 
Monocotyledonous  fibres,  97,  238 
Mordants,  testing  for,  in  silk  fabrics,  260 
Morocco  sheep,  7 
Morvant  de  la  chine,  7 
Motus  multicaidis,  69 
Mungo,  50 
Musa  cavendishii,  202 

eusete,  202 

mindanensis,  202 

patadisaica,  100,  202 

sapientium,  202 

text  His,  loo,  191,  192,  202, 
Musk  mallow,  237 
Mysore  sheep,  7 

N. 

Nankin  cotton,  121 

Nepal  sheep,  7 

"Neps,"  129 

Neri  silk,  72 

Netting  fibres,  103 

Nettle  fibre,  100 

New  Zealand  flax,  100,  192,  199,  239,  242 

analysis  of,  201 

distinction  of  from  other  fibres,  215 

uses  of,  20 1 

Nitrated  cotton,  microscopy  of,  173 
Nitric  acid,  action  of,  on  cotton,  149 

on  wool,  37 
Nitrogen  in  cotton,  142 

in  wool,  to  show  presence  of,  28 
Nitrous  acid,  action  of,  on  wool,  37 
Noils,  24 

Norfolk's  cotton,  127 
Nurma  cotton,  115 


O. 


Ochroma  lagopus,  121,  231 
Octonitro-cellulose,  171 
Oharwar  cotton,  i  .s 
Oomrawuttee  cotton,  119,  125,  127 

i(    ;K  iiN,  action  of,  on  wool,  39 
Organzine  silk,  83 
Orleans  cotton,  120,  125,  126 


Onate  vegetal,  121 
Ovis  ammon,  6 

guinensis,  7 
aries,  6 

angolensis,  7 

conge nsis,  7 

numccda,  7 

steatiniora,  j 
barnal,  7 
cagia,  i 
ethiopia,  7 
grienensis,  7 
hispaniam,  6 
laticandatus,  7 
longicandatus,  7 
musmon,  6 
polyceratus,  7 
rusticus,  6 
selingia,  7 
strepsiceros,  6 

Oxalic  acid,  action  of,  on  cotton,  151 
Oxycellulose,  150,  154 

P. 

Packing  fibres,  105 

Palm  papers,  105 

Palmetto  fibre,  104 

Palmyra  fibre,  104 

Pandanus  odoratissimus,  99 

Pangane  hemp,  192 

Paper  material,  105 

Paper  mulberry  fibre,  100 

Paracellulose,  147 

Paraiba  cotton,  125,  126 

Pattes  de  lievre,  121 

Pectin,  action  of  fatty  acids  on,  179 

fermentation,   179 
Pectocelluloses,  146 
Pectose,  147 
Peelers  cotton,  127 
Perces  silk,  72 

Pernambuco  cotton,  120,  125 
Pernams  cotton,  126 
Peruvian  cotton,  115,  118,  125 

varieties  of,  126 
Piassave  fibre,  109 

Picric  acid  solution  for  fibre-testing,  212 
Pigment  matter  in  wool,  22 
Pile  fabrics,  determination  of  silk  in,  255 
Pineapple  fibre,  100,  206,  234,  241 
Piques  silk,  72 
Pita  fibre,  99,  109,  192,  204 

hemp,  192,  240,  242 
Phcnix  dactylijera,  100 
Pliormlum  tenax,  99,  100,  192,  IQQ 
Plaiting  fibres,  104 
riant  fibres,  anatomical  classification  of,. 

"7 
Plumose  fibres,  106 


INDEX. 


Plush,  analysis  of,  256 
Polarized  light,  action  of  on  plant  cell- 
membranes,  106 

action  of  on  silk,  91,  222 
Pool-retting  of  flax,  178 
Poplar  cotton,  226 
Pseudo -fibres,  102 
Pseudo-jute,  237,  245 
Pua  hemp,  192 
Pucha  sheep,  7 
Pulled  wool,  24 
Pulu  fibre,  122 
Pyroxylin,  150 

silks,  171 


Q. 

Qualitative  analysis  of  fibres,  tables  for, 

209,  210 

Quality  of  wool,  influences  affecting,  25 
Queensland  cotton,  127 
hemp,  192 


R. 

Rabbit-hair,  65 

Rama  limpa  cotton,  121 

Ramie,  09,  100,  188,  233 

fibre,  analysis  of,  191 
microscopy  of,  191 
physical  properties  of,  189 
Rangoon  cotton,  128 

hemp,  192 

Raphia  tcetigera,  100 
Raw  cotton,  analysis  of,  142 

silk,  microscopy  of,  76 

wool,  fatty  matters  in,  32 
mineral  matters  in,  32 
potash  salts  in,  34 
Red  Peruvian  cotton,  126 
Reed-mace  hair,  225 
Regain  in  conditioning,  46 
Regenerated  cellulose,  146 
Retting  flax,  177 

chemical  methods  for,  178 

Schenck's  method  of,  179 
Rhea  fibre,  188 
Rhus  typhina,  192 
Ribbon  basts,  103 
Ricotti  silk,  72 
Rio  Grande  cotton,  126 
Rippling  flax,  177 
Roa  fibre,  233 
Ronoaks  cotton,  127 
Rope  fibres,  tensile  strength  of,  206 
Roselle  hemp,  192 

Rough  Peruvian  cotton,  120,  125,  126 
Rough-weaving  fibres,  104 
Rugginose  silk,  72 
Russian  hemp,  206 


S. 

Saccharum  officinale,  226 
Salix  alba,  100 
Sansevieria  cylindrica,  192 
fibre,  100,  239 
guinensis,  191 
kirkii,  192 
longiftora,  191 
roxburghiana,  191 
Santos  cotton,  120,  126 
Sarothamnus  vulgaria,  100 
Saturnia  cecropia,  222 
Polyphemus,  221 
spini,  221 

Scales  on  wool,  number  of  per  inch,  18 
Schlerenchymous  fibres,  98,  106 
Schreiner  process  of  lustring  cotton,  169 
Schweitzer's  reagent  for  fibre-testing,  211 
Scinde  cotton,  119,  125,  128 
Sea  grass,  97 
Sea-island  cotton,  114,  115,  117 

varieties  of,  126 
Sea-wrack,  97 
Sebaceous  glands,  10 
Seed-hairs,  97 

structure  of,  98,  106 
Senegal  silk,  action  of  polarized  light  on, 

223 
Sericin,  85 

chemical  composition  of,  89 
chemical  reactions  of,  90 
method  of  preparingr  90 
Serin,  90 

Sesbania  macrocarpa,  191 
Shaymblian  sheep,  7 
Sheep,  classification  of,  6 
Shoddy,  50 

determination  of,  52 
microscopy  of,  51 
Short-tailed  sheep,  7 
Sida  retusa,  99,  109,.  192 
Silk,  action  of  acids  on,  91 
alkalies  on,  92 
basic  zinc  chloride  on,  93 
chlorine  on,  93 
coloring-matters  on,  93 
concentrated  acids  on,  92 
copper  oxide  on,  93 
hydrofluoric  acid  on,  93 
hydrofluosilicic  acid  on,  93 
metallic  salts  on,  91 
nickel  oxide  on,  93 
nitric  acid  on,  92  , 

sodium  chloride  on,  91 
sugar  on,  91 
tannic  acid  on,  91 
amount  of  ash  in,  86 
analysis  of,  86 
chemical  constitution  of,  85 


286 


INDEX. 


Silk,  chemical  reactions  of,  91 

coloring -matter  in,  91 

conditioning  of,  80 

density  of,  82 

determination  of  in  fabrics,  256 

electrification  of,  81 

hygroscopic  properties  of,  80 

lustre  of,  8 1 

physical  factors  of,  82 

physical  properties  of,  74 

qualitative    distinction  of  from   other 
fibres,  213 

scroop  of,  82 

strength  of,  82 

thickness  of  in  cocoon,  72 

and  cotton  fabrics,  analysis  of,  252 

cocoon,  dimensions  of,  68 

culture,  history  of,  69 

in  America,  69 
Silk  fibre,  chemical  composition  of,  86 

thickness  of,  221 
Silk-glue,  85 

discharging  of,  85 
Silk -grass,  206 
Silk-reeling,  83 
Silk -shoddy,  72 
Silk- wool,  41 
Silkworm,  68 

its  method  of  spinning,  71 
Silkworms,  annual,  69 

method  of  cultivation  of,  70 

poly vol tine,  69 

Silver  nitrate  solution  for  fibre-testing,  211 
Sisal  hemp,  192,  203 
Slag  wool,  4 
Smooth-haired  sheep,  7 
Smooth  Peruvian  cotton,  120,  125,  126 
Smyrna  cotton,  119,  125,  127 
Sodium  nitroprusside  solution  for  fibre- 
testing,  211 

plumbite  solution  for  fibre-testing,  211 
Spanish  moss,  105 

sheep,  6 

Spartium  junccum,  TOO 
Specific  gravity  of  fibres,  262 
Spinning  fibres,  102 
Sponia  ivightii,  99 
Spun  glass,  3 

silk,  83 
"Staff,"  105 

Stannic   chloride  solution  for  fibre-test- 
ing, 209 
Stearerin,  33 

Stegmata  in  Manila  hemp,  202 
Stcrculia  villosa,  99 
Stiffening  fibres,  105 
St.  Louis  cotton,  127 
Straw  plaits,  104 
Strophunthus,  99,  122 
Structural  fibres,  101 


Strussa  silk,  72 

Stuffing  fibres,  104 

Sugar-cane  hairs,  226 

Suint,  33 

Sulphur  in  wool,  amount  of,  30 

effect  of  in  dyeing,  29 

manner  of  combination,  30 

manner  of  removing,  30 

to  show  presence  of,  29 
Sulphuric  acid,  action  of  on  wool,  37 
Suun  hemp,  99,  100,  109,  192,  197,  234, 
246 

analysis  of,  198 
Surat  cotton,  119,  128 
Surface  fibres,  101 
Surinam  cotton,  125 
Swedish  hemp,  192 

T. 

Table  of  reactions  of  animal  and  vege- 
table fibres,  214 
Tahiti  cotton,  119,  125,  126 
Tame  sheep  of  Cabul,  7 
Tampico  hemp,  192 
Tannic  acid,  action  of  on  wool,  39 
Tarmate  silk,  72 
Tartary  sheep,  7 
Tennessee  cotton,  125,  127 
Tensile  strength  of  wool  fibre,  20 
Tetranitro-cellulose,  150 
Texas  cotton,  125,  126 
Textile  fibres,  quantitative  analysis  of,  247 

papers,  105 

Thermochemical  reactions  of  wool,  38 
Thespesia  lampas,  99,  109 
Thibet  goat,  6 

wool,  51 

Tie  material,  103 
Tilia  euro  pa,  100 
Tillandsia  fibre,  99,  109 
Tinnevelly  cotton,  119,  125,  128* 
Tops,  24 
Tram  silk,  84 
Tree-basts,  103 
Trinitro-cellulose,  150,  171 
True  silk,  action  of  polarized  light  on,  222 

distinction  of  from  wild  silks,  217 
Tungstic  acid,  action  of  on  cotton,  151 
Turkish  cotton,  128 
Tussah  silk,  74 

action  of  polarized  light  on,  223 

Analysis  of,  94 

analysis  of  ash  of,  94 

chemical  properties  of,  94 

difference  of  from  true  silk,  95 

microscopy  of,  78 

Type  of  shi-rp,  influences  determining,  7 
Typha  angusti/olia,  225 
Tyrosin,  production  of  from  fibroin,  88 


INDEX. 


287 


U. 

Upland  cotton,  114,  116,  120,  125,  127 
Urena  sinuata,  99,  109,  238,  245 
Urtica  dioica,  100,  192 
nivea,  100 


V. 

Vanduara  silk,  173 
Vascular  fibres,  97 
Vasculose,  147 
Vegetable  fibres,  i 

analytical  review  of,  241 

classification  of,  100 

color  of,  1 08 

Cross     and     Bevan's     method     for 

determining,  212 
hygroscopic  moisture  in,  109 
lustre  of,  1 08 

micro-analytical  tables  for,  223 
table  for  determination  of,  232 
down,  121,  226,  243 
microscopy  of,  121 
parchment,  148 
silk,  99,  121,  226,  243 
Vicogne,  59 

yarn,  61 
Vicuna,  59 
Vicuna  wool,  61 
Viscose,  153 

silk,  176 
Vulcanized  fibre,  148 


W. 


Wadding  silk,  72 

Waste  silk,  72 

Water  hemp,  192 

Watt  silk,  >c 

Waves   in    wool    fibre,    number   of   per 

inch,  20 

Waviness  of  wool  fibre,  19 
manner  of  removing,  20 
Weighted  silk,  analysis  of,  265 
Weighting,  determination  of  in  silk,  258, 

262 

materials  in  silk,  259 
West  Indian  cotton,  121,  125 

varieties  of,  127 
sheep  of  Jamaica,  7 
Western  Madras  cotton,  119 
Westerns  cotton,  128 
White  Egyptian  cotton,  120,  125,  126 
Wild  hemp,  192 
silks,  73 

microscopy  of,  77,  90 
Willesden  canvas,  147 


Wodomalam  cotton,  125 
Wood-pulp  fibre,  105 
Woody  fibre,  101 
Wool,  action  of  acid  salts  on,  42 
alkalies  on,  39 
alkaline  carbonates  on,  39 
artificial  heat  on,  44 
barium  hydroxide  on,  41 
bromin  on,  41 
chlorin  on,  41 
coloring-matters  on,  42 
milk-of-lime  on,  41 
neutral  salts  on,  41 
oxidizing  agents  on,  41 
volatile  alkalies  on,  41 
analysis  of,  28 
chemical  constitution  of,  28 
hygroscopic  nature  of,  43 
manner  of  drying,  44 
physical  elements  of,  10 
physiology  of,  9 
proper  drying  of,  45 
special  meaning  of  term,  6 
water  of  hydration  in,  44 
and  cotton  fabrics,  analysis  of,  247 
and  silk  fabrics,  analysis  of,  251 
Wool-bearing  animals,  6 
Wool,  cotton,  and  silk  fabrics,  analysis 

of,  252 
Wool-fat,  10 
Wool     fibre,     action     of     concentrated 

mineral  acids  on,  39 
dilute  acids  on,  37 
heat  on,  31 
hot  water  on,  31 
chemical  composition  of,  31 
chemical  elements  in,  28 
chemical  reactions  of,  35 
classification  of,  27 

conditions  influencing  structure  of,  53 
decomposition  products  of,  32 
diameter  of,  24 

distillation  of  with  caustic  potash,  32 
dry  distillation  of,  32 
length  of,  24 
microscopy  of,  13 
mineral  matter  in,  34 
morphology  of,  n 
qualities  of  as  a  textile  fibre,  5 
the  typical,  14 
Wool-grading,  8 
Wool-hair  of  sheep,  8 
Wool-mixes,  54 
Wool-oil,  ii 

Wool-sorter's  disease,  59 
Wool-sorting,  8 

divisions  of  fleece  in,  8 
Wool  substitute,  50 
Woolen  yarns,  25 
Worsted  yarns,  24 


288 


INDEX. 


X. 

Xanthoproteic  acid,  37 

Y. 

Yama-mai  silk,  action  of  polarized  light 
on,  223 


]   Yenu  sheep,  7 
Yucca  fibre,  100,  240,  241 

Z. 

Zeylan  «heep,  7 

Zinc  chloride  solution  for  fibre-testing,  209 
Zoster  a  marina,  97 


I,  AST 


Tr-^-v,°oo  -  - 


Y 


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